Edited by Jürgen Basedow, Giesela Rühl, Franco Ferrari and Pedro de Miguel Asensio
Chapter U.3: Uniform substantive law and private international law
I. Definition of uniform law – and types of uniform law
The expression ‘uniform law’ indicates a set of identically worded legal rules that are binding on a general level in more than one jurisdiction where they are also supposed to be interpreted and applied in the same manner. Actually, for such sets of rules to be considered uniform law, they must have been created with the intention to be interpreted and applied in one and the same manner throughout the jurisdictions where they are in force. Where this so-called animus unificandi is lacking, it may well be possible for the laws of different jurisdictions to be identical to each other, but they will nevertheless not constitute uniform law. This is why, for instance, the spontaneous, unintentional creation of identically worded legal rules in different jurisdictions as an answer to similar problems arising in practice do not constitute uniform law. The same is true as regards the unilateral reception of foreign legal rules – even though this may lead to legal rules of various jurisdictions being identical.
Law that is simply ‘harmonized’, that is, law that has not been created with the intention of getting rid of the existing differences, but rather with the goal of merely reducing those differences (as is the case for the law originating from most EU directives), does not constitute uniform law. This does not mean that only those legal rules that fully correspond to each other can be considered uniform law. If this were the case, it would be impossible to ever speak of uniform law, as fully corresponding legal rules are very rare, even where the wording of the legal rules is identical. The reasons for divergence are manifold, such as the fact that the uniform texts are often drafted in different languages and are interpreted and applied differently in practice (see Tribunale di Rimini, 26 November 2002  Giur. it. 896). Therefore, the starting point for determining whether there is uniform law is the degree of intended similarity of the legal rules in question. Where the maximum degree is intended, ie where the law is supposed to be one and the same, uniform law may exist despite any factors that may have a negative impact on the uniformity aimed at. Where, however, from the outset, the efforts are merely aimed at the creation of a similar, harmonized law, one cannot speak of uniform law.
While, as just mentioned, the intended identity of the legal rules defines uniform law, for the purpose of that definition the area of law to be unified is utterly irrelevant. This is due to the fact that the expression ‘uniform law’ indicates not so much an area of the law as a status, but how the law is (supposed to be). Consequently, efforts towards the creation of uniform law can relate to the most disparate areas of law. For the purpose of this entry, it is relevant to point out by way of example that they can relate to the areas of private international law as well as substantive law.
As regards the latter, a distinction has to be made between unlimited and limited uniform substantive law. Unlimited uniform substantive law is constituted by those legal rules that also govern purely domestic situations, which is why this kind of uniform substantive law is rather rare (although there are a few examples of such uniform law, such as the rules laid down by the Convention of 7 June 1930 for the Settlement of certain Conflicts of Laws in connection with Bills of Exchange and Promissory Notes (143 LNTS 317) and the Geneva Cheques Convention (Convention of 19 March 1931 for the Settlement of certain Conflicts of Laws in connection with Cheques, 143 LNTS 407)). Limited uniform substantive law, on the other hand, solely governs trans-border situations, that is, situations that have a relationship to more than one country. Unlike unlimited uniform substantive law, limited substantive law does not per se have an impact on domestic law. This is an advantage insofar as it allows a given state to enter a limited uniform substantive law instrument into force even where it contrasts with that state’s domestic law. This means that the adoption of limited uniform substantive law does not require a high degree of compatibility vis-à-vis the domestic substantive law. The same is true with uniform private international law because it has an impact solely at the conflict-of-laws level rather than the substantive one. Such uniform private international law may, however, override domestic private international law rules, which, at times, may cause problems, as this entry will show.
A high degree of compatibility is, however, a prerequisite for the success of any effort towards the creation of unlimited uniform substantive law, which is why there are areas of law in relation to which unlimited uniform substantive law will be nearly impossible. In this respect, it may p. 1773suffice to mention areas such as family law and the law of →succession – areas characterized by national particularities originating from nation-specific social, ideological, religious and cultural values and backgrounds which national legislatures will hardly give up. Even though limited uniform substantive law would not impact on the existing national particularities in these areas, insofar as the domestic law would still apply to (purely) domestic situations, limited uniform substantive law in these areas is very rare as well since these areas are far too influenced by the aforementioned values to allow for even the creation of a limited uniform substantive law.
In the aforementioned areas, one can find, however, uniform private international law. This is due to the fact that private international law is – as much as its →connecting factors – influenced to a much lesser extent than its substantive counterpart by such particularities and values. In other words, it is much easier to forego domestic private international law rules than substantive rules, since the former are rarely the expression of deeply rooted cultural, sociological, ideological or religious beliefs. This is why, to give just a few examples, there is a Hague Convention of 24 October 1956 on the law applicable to maintenance obligations towards children (510 UNTS 161), but no substantive law convention addressing those obligations. The same can be said in respect of substantive law conventions (and the lack thereof) governing the topics addressed in other private international law conventions, such as the Hague Testamentary Dispositions Convention (Hague Convention of 5 October 1961 on the conflicts of laws relating to the form of testamentary dispositions, 510 UNTS 175), the Hague Matrimonial Property Convention (Hague Convention of 14 March 1978 on the law applicable to matrimonial property regimes, 16 ILM 14), and the Hague Marriage Convention (Hague Convention of 14 March 1978 on Celebration and Recognition of the Validity of Marriages, 1901 UNTS 131) etc.
II. Aims and goals of uniform substantive law versus those of uniform private international law
At this point one must wonder what goals the unification of law pursues and whether the distinction between uniform substantive law and uniform private international law influences not only the possibility of unifying certain areas of law, but also has an impact on the goals behind the unification process. The starting point is the realization that unification of law does not in itself constitute a goal that is to be pursued at all costs, independently from any valid justification. Instead, unification of law has to aim at more than ‘just’ obtaining unified law. The issue of which other goals may justify the unification of law depends, in part, on the area of law (such as private international or substantive law) to be unified, as the goals of unification of one area may differ from those of a different area.
Of course, efforts towards the unification of different areas of law may also pursue the same goals. For example, one of the goals behind the unification of both substantive law and private international law is to avoid the unequal treatment to which the application of different legal rules may lead to in a specific instance. This does not mean, however, that in light of that common goal, the distinction between private international law and substantive law becomes irrelevant. This is due to the fact that private international law and substantive law have an impact on different levels. With respect to avoiding unequal treatment, uniform private international law guarantees that the courts of the states in which it is in force apply the same substantive law. This leads to uniformity on a conflict-of-laws level. Consequently, parties have (apart from the cases of →dépeçage) merely to provide for the application of one substantive law. There is a downside to this: courts may well have to apply an unfamiliar law, which leads to uncertainty and costs arising from the determination of the contents of that unfamiliar (foreign) law. In any case, it should be mentioned that uniform private international law cannot prevent all unequal treatment. For example, the party whose law will ultimately be applicable will have an advantage, insofar as that party will have no difficulties nor will that party incur any costs in determining the contents of the applicable law. Uniform substantive law, on the other hand, guarantees that all parties from countries where it is in force will have equal access to the substantive law solutions, thus ‘levelling the playing field’ – at least among the parties of states in which that uniform law is in force. The fact that uniform substantive law always deals with the situations falling within its sphere of application in the same manner (at least as a starting point), while uniform private international law merely guarantees resort to p. 1774the same substantive law, also avoids unequal treatment.
The goal of uniform substantive law for international situations most often referred to is a different one. It involves making the application of law easier by creating a (substantive) law that, according to the prevailing view, avoids the need to resort both to private international law – considered to be rather complicated – and to the applicable law determined by means of that very same private international law. This promotes certainty of law, makes business decisions easier and facilitates risk assessment. According to the prevailing view, this leads to a reduction of costs, benefiting not only the parties involved but the economy as a whole. Therefore, where no resort to private international law is had, an important source of uncertainty is avoided which, in turn, certainly saves costs.
The foregoing assumption leads some commentators to suggest that the unification of substantive law rules is, where at all possible, to be preferred over the unification of private international law rules, on the grounds that uniform substantive law rules are ‘of a higher level’ or ‘superior’ vis-à-vis uniform private international law rules. Whether this is true or not is not relevant here. What is relevant, however, is that whenever the court of a contracting state to a given uniform substantive law convention has to determine the substantive rules to apply to an international situation prima facie governed by that convention, the court must first look into whether that convention applies rather than resort to its own private international law rules. This result has been justified both by commentators and courts on two grounds: first, that the rules of a uniform substantive law convention are more specific insofar as their sphere of application is more limited; and further, that they lead directly to a substantive solution, while resort to private international law requires a two-step approach, that is, the identification of the applicable law and the application thereof (see Tribunale di Vigevano, 12 July 2000 (2001) 20 J.L.& Com. 209).
It must be pointed out, however, that this prevalence of uniform substantive law vis-à-vis private international law (irrespective of whether it is uniform or not) does not necessarily lead to the conclusion, incorrectly drawn by some commentators, that resort to private international law is irreconcilable with the uniform substantive law approach. This statement, not unlike similar ones suggesting that uniform substantive law can do away with recourse to private international law, is incorrect. It is time to recognize that there are many reasons why a private international law analysis cannot be excluded despite the existence of uniform substantive law conventions. And this is true even in respect of uniform substantive law instruments, such as the ULIS (Convention of 1 July 1964 relating to a Uniform Law for the International Sale of Goods, 834 UNTS 107) and the ULF (Convention of 1 July 1964 relating to a Uniform Law on the Formation of Contracts for the International Sale of Goods, 834 UNTS 169), which contain provisions explicitly stating that for the purposes of their application private international law rules are to be excluded. In effect, even under these instruments it was incorrect to state that resort to private international law rules was precluded. As one commentator correctly pointed out in respect of the ULIS and ULF, ‘[e]ven the adoption of the Uniform Law[s] everywhere in the world would not exclude the need for conflicts rules . . . . In the end, the blackballed rules of private international law will have to be rediscovered and resorted to’ (Kurt Nadelman, ‘The Conflicts Problems of the Uniform Law on the International Sale of Goods’  Am.J.Comp.L. 236, 239–40). But it cannot be doubted that provisions such as the aforementioned ones make it more difficult to depart from the more traditional way of seeing the relationship between uniform substantive law and private international law as an antagonistic one and, thus, to see that there is room for resort to private international law even where a uniform substantive law instrument is in force in the forum state.
III. Express and implicit references to private international law in uniform substantive law conventions
One reason why it is incorrect to state that resort to private international law can be completely forgone where uniform substantive law conventions exist is due to the fact that many uniform substantive law conventions, albeit neither the ULIS nor the ULF, refer themselves to private international law, where they do not put forth private international law rules themselves.
By way of example of the latter, it may be worth referring to the UNIDROIT Financial Leasing Convention (UNIDROIT Convention p. 1775of 28 May 1988 on International Financial Leasing, 2312 UNTS 195; →Financial leasing (uniform law)), which itself sets forth a rule of private international law, namely art 7(3). That provision identifies the law applicable to decide which, if any, public notice requirements must be met in order for the lessor’s real rights in the equipment leased to be valid against execution creditors or the lessee’s trustee in bankruptcy. Similarly, chapter VI of the Convention on Independent Guarantees and Stand-by Letters of Credit (2196 UNTS 163) sets forth the rules of private international law. The most elaborate set of rules of private international law can, however, be found in the UNCITRAL Assignment of Receivables Convention (United Nations Convention on the Assignment of Receivables in International Trade, concluded 12 December 2001, adopted by resolution A/RES/56/8). This Convention contains not only a private international law rule for priority (art 22), but also what has been labelled a ‘mini-convention’ of private international law. While the rule for priority applies whenever the Convention itself applies due to all of its applicability requirements being met, Chapter V, which contains an elaborate set of rules (dealing with the law applicable to the formal requirements of the assignment, the law applicable to the mutual rights and obligations of the assignor and the assignee, as well as the law applicable to the rights and obligations of the assignee and the debtor) has a much broader sphere of application, as it also applies as long as one of the alternatively listed internationality requirements set forth in the Convention (art 1(4)) is met, and this is even if the other applicability requirements (such as those ratione materiae) are not met.
As regards the references to private international law in uniform substantive law conventions, there are many, including many express ones. The UNIDROIT Convention on International Financial Leasing, for instance, expressly refers to ‘private international law’ on several occasions, namely in arts 6(2), 7(5)(b) and 8(4) (→Financial leasing (uniform law)). Express references to ‘private international law’ can also be found in other uniform substantive conventions, such as the →CISG (United Nations Convention of 11 April 1980 on Contracts for the International Sale of Goods, 1489 UNTS 3), the Ottawa Factoring Convention (UNIDROIT Convention on International Factoring of 28 May 1988, 2323 UNTS 373, 27 ILM 943) (→Factoring (uniform law)) etc. Where these instruments refer to ‘private international law’, the reference is to be understood as to the ‘private international law’ of the forum, unless, of course, a given instrument provides for private international law rules itself.
If one looks at the context in which such express references are made as well as at the context in which some of these instruments rely on a private international law analysis, as do, for instance, the UNIDROIT Convention on International Financial Leasing in art 3(1)(b), and the Ottawa Factoring Convention in art 2(1)(b), one can see how important resort to private international law is. In effect, the provisions just mentioned are particularly important, as they show that the applicability of the foregoing conventions themselves depends (where these conventions are not applicable due to all parties to the contract having their relevant place of business in contracting states) on a private international law analysis. The same is true, for instance, in respect of art 1(1)(b) CISG, which states that the CISG applies ‘when the rules of private international law lead to the law of a contracting State’. These provisions unambiguously show that resort to private international law may be necessary even for the purpose of applying a uniform substantive law convention.
IV. Limitations to the sphere of application as a reason for the need to resort to private international law
As mentioned earlier, all recent uniform substantive law conventions merely set forth limited uniform law, ie uniform law that only governs situations linked to more than one jurisdiction. Furthermore, all conventions that are limited in the aforementioned way define internationality in a given way. This means, inter alia, that where a relationship is not international as per the definition contained in the relevant convention, the convention cannot per se be applicable, even though the relationship may still be international. This, in turn, requires resort to a private international law analysis to determine which law applies to that relationship.
By way of example, it may suffice to recall the definition of internationality found in art 2(1) of the UNIDROIT Convention on International Factoring. Unlike, for instance, the →CISG, the Ottawa Factoring Convention (→Factoring (uniform law)p. 1776) does not define internationality on the basis of the location of the place of business of the parties to the contract it governs. Therefore, even factoring contracts concluded between parties having their places of business in the same state can be subject to the Convention de quo, provided that the ‘internationality’ requirement, as well as all the other requirements, are met. According to the Convention, the internationality of a factoring contract depends on an objective rather than a subjective element. By virtue of art 2(1), a factoring contract is international when the receivables assigned arise either from an ‘international’ contract for the sale of goods (between suppliers and debtors with places of business in different states) (→Sale contracts and sale of goods) or an ‘international’ contract for the supply of services (the parties to which have their places of business in different states). Consequently, the Convention’s applicability depends not as much upon the ‘internationality’ of the factoring contract as upon the ‘internationality’ of the receivables. This means, however, that the assignment of domestic receivables between suppliers and factors who have their relevant place of business in different states cannot fall under the Convention’s international sphere of application, even though the factoring contract is certainly ‘international’. For these types of situations, resort to private international law is necessary to identify the applicable law.
The CMR (Convention of 19 May 1956 on the contract for the international carriage of goods by road, 399 UNTS 189) also does not define the internationality of the contracts it governs on the basis of the location of the place of business of the parties. In effect, pursuant to that Convention, the contracts for carriage of goods are international, ‘when the place of taking over of the goods and the place designated for delivery, as specified in the contract, are situated in two different countries’ (art 1(1) CMR). This, of course, excludes very many types of international contracts for the carriage of goods by road from that Convention’s international sphere of application, thus making it necessary to often determine the applicable law on the basis of the rules of private international law (of the forum) (→Carriage of goods by road, rail and inland waterways).
At this point, it is worth pointing out that not only is the international sphere of application of all recent uniform substantive law conventions limited, but so too is their substantive sphere of application, thus making it again necessary to identify the law applicable to the international contracts falling outside a particular convention’s substantive sphere of application (at least where no other uniform substantive law convention governs).
By way of example, it suffices to recall the limitations to the substantive sphere of application found in art 2 CISG. Pursuant to this provision, the →CISG does not extend to the sale of ships, airplanes, stocks, shares, investment securities, negotiable instruments, money, electricity as well as the sale by auction, sales on execution or otherwise by authority of law. It further does not apply to the sale of goods bought for personal, family or household use, unless the seller, at any time before or at the conclusion of the contract, neither knew nor ought to have known that the goods were bought for any such use. Other conventions have similar carve-outs. The CMR, for instance, expressly states that it does not apply ‘to carriage performed under the terms of any international postal convention, funeral consignments and furniture removal’ (art 1(4) CMR). The UNIDROIT Financial Leasing Convention excludes, for instance, leasing contracts that take the form of operating leasing from its sphere of application. Although this is not expressly stated in the Convention, it can be derived from the fact that the Convention only applies to leasing contracts where the rentals payable under the leasing agreement are calculated so as to take into account in particular the amortization of the whole or a substantial part of the cost of the equipment, since operating leasing is from the outset not aimed at full or substantial amortization of the assets. By way of final example, it is worth recalling that the Ottawa Factoring Convention only governs factoring contracts requiring, among others, that notice of assignment be given to the debtor (art 1(2)(c)), thus excluding the Convention’s application to non-notification factoring contracts. Furthermore, as per its art 1(2)(a), the Convention does not apply where the receivables assigned arise from contracts for the sale of goods bought primarily for their personal, family or household use, thus limiting the substantive sphere of application to notification factoring.
V. p. 1777The impact of reservations on the need to have recourse to private international law
Most recent uniform substantive law conventions allow contracting states to declare a limited number of reservations, so as to provide some flexibility to a type of instrument the rigidity of which would otherwise lead some states to outright reject it. The possibility to declare such reservations impacts, however, on the uniformity aimed at. Furthermore, where states declare such reservations, they also trigger the need to resort to a private international law analysis.
The reservation contained in a uniform substantive law convention that has probably drawn the most attention is the reservation declared by various contracting states to the →CISG in relation to art 95. Pursuant to this provision, contracting states may declare that they will not be bound by art 1(1)(b) CISG, pursuant to which the CISG also applies ‘when the rules of private international law lead to the law of a Contracting State’. Although there is disagreement as to the exact effects of declaring this type of reservation, there is agreement on the fact that it has private international law implications.
Although other uniform substantive law conventions contain provisions comparable to art 1(1)(b) CISG (such as art 2(1)(b) Ottawa Factoring Convention and art 3(1)(b) UNIDROIT Convention on International Financial Leasing), these conventions do not provide for the possibility to declare a reservation relating to the operation of those provisions. There are, however, some reservations that all recent uniform substantive law conventions allow contracting states to declare. In this respect, it may be sufficient to refer to the so-called ‘federal state clause’, contained, for instance in art 93 CISG, art 18 ILC, art 17 IFC as well as in art 18 of the UNCITRAL Electronic Communications Convention (United Nations Convention of 23 November 2005 on the Use of Electronic Communications in International Contracts, adopted on 23 November 2005 during the 53rd plenary meeting of the General Assembly by resolution A/60/21, text available in UN doc A/60/515) and art 35 of the UNCITRAL Assignment of Receivables Convention. These provisions all allow a state that is divided into several territorial units in which, according to that state’s constitution, different systems of law are applicable in relation to the matters dealt with in the relevant convention, to make a declaration pursuant to which the convention does not extend to all territorial units. Where a state made such a declaration and a party to a contract has its place in a territorial unit to which the convention does not extend, that party is considered to have its place of business in a non-contracting state, thus triggering, once again, a private international law analysis which may either lead to the application of the convention or to a domestic law.
Many recent uniform substantive law conventions also allow states to declare another reservation that has private international law consequences. For instance, pursuant to art 94 CISG, art 17 IFC and art 19 ILC, contracting states which have the same or closely related legal rules on matters governed by the relevant convention may declare that the convention is not to apply where the parties to the contract the convention governs and, in the case of the IFC and the ILC, the parties to the underlying contract, have their place of business in those states. The rationale behind this provision is to render the conventions inapplicable to contractual relationships between parties that have their places of business in states that have a law that is largely uniform, thus allowing regional unification efforts not to be overridden by the existence of the conventions drafted on a more global level. Consequently, where the potentially applicable convention does not apply, resort is once again to be made to the private international law rules of the forum to determine the applicable law.
Some conventions also allow states to declare reservations that, unlike the aforementioned ones, do not have an impact on the status of a contracting state, but rather on the substance. Despite the different impact, what these reservations have in common is that they all trigger the need for a private international law analysis. By way of example, it may suffice to recall the art 96 reservation, which has an impact on the formal validity of contracts for the international sale of goods generally governed by art 11 of the CISG, which sets forth the principle of freedom from form requirements. This principle does not necessarily apply where at least one of the parties to the contract governed by the →CISG has its place of business in a state that has declared a reservation under art 96 CISG. In this line of cases, any provision ‘that allows a contract of sale or its modification or termination by agreement or any offer, acceptance or other indication of intention to be made in any form other than in writing does not apply’. What consequences p. 1778this has on the applicable writing requirements is subject to dispute. What is undisputed, however, is the fact that a private international law analysis is required to determine whether any form requirements have to be met.
It may be worth pointing out that the IFC also allows for a reservation with substantive effects. Pursuant to art 18, states may at any time make a declaration that an assignment made in breach of a non-assignment clause shall not be effective against the debtor when, at the time of conclusion of the contract of sale of goods, the debtor has its place of business in that state. This provision does not, however, require resort to private international law, at least not in the courts of states declaring the reservation at hand, as the provision itself sets forth the substantive consequences of declaring the art 18 reservation.
VI. Limitations to the scope of application and party autonomy as reasons for resort to private international law
All uniform substantive law conventions, without exception, fail to constitute exhaustive bodies of rules. In other words, no uniform substantive law convention provides solutions to all matters that may arise in relation to the specific relationships it governs. This, however, means that resort to private international law may be necessary to determine the law applicable to the issues falling outside a given convention’s scope of application.
In effect, it is generally through resort to private international law that the law applicable to matters excluded from the limited scope of application of these conventions, the so-called ‘external gaps’, are to be settled. This is provided, of course, that no other uniform substantive convention takes precedence, as does, under certain conditions, the 1974 Convention on the Limitation Period in the International Sale of Goods (Convention of 14 June 1974 on the Limitation Period in the International Sale of Goods, 1151 UNTS 3; 13 ILM 952) in relation to the statute of limitations issue not governed by the →CISG.
The private international law approach is completely different from the one to be adopted in respect of the so-called ‘internal gaps’, ie matters governed by a convention which, however, are not expressly settled in it, which requires resort to private international law only as ultima ratio, when it is not possible to solve the matter from within the relevant convention, that is through recourse to the general principles upon which the convention is based. From the foregoing, it becomes apparent how important the distinction between the various types of gaps and their identification really is. Unfortunately, however, the various uniform substantive law conventions do not set forth specific criteria on the basis of which to make the distinction. Some conventions do, however, expressly list some issues that they do not settle. Article 4 CISG, for instance, provides a (non-exhaustive) list of matters with which the CISG is not concerned. This includes the validity (other than the formal validity) of the contract or of any of its provisions or of any usage as well as the effect which the contract may have on the property in the goods sold. Article 5 CISG also lists a matter with which the CISG is not concerned, namely the liability for death or personal injury caused by the goods to any person. The ILC, too, expressly identifies some issues with which it is not concerned, such as the liability of the lessor in respect of the equipment in his capacity as owner (art 8(1)(c)) and accounting and taxation issues (Preamble).
Although some conventions do not contain a list of matters not governed by them, their scope of application is still limited. In this respect, it may suffice to point out that the IFC, for instance, does not deal with matters of general contract law, such as formation of contract, validity, damages, statute of limitations etc. Nor does the IFC deal with all matters more specifically relating to factoring, such as the third-party effectiveness of assignments of receivables and the priority among conflicting claimants as to the accounts receivable. These matters have to be settled through the law applicable pursuant to the rules of private international law.
Of course, the fact that some of the conventions contain a list of matters excluded from their scope does not limit the matters excluded to the ones listed. Among the matters identified by courts and commentators as not being at all governed for instance by the →CISG are, among others, the validity of a choice of forum clause (→Choice of forum and submission to jurisdiction), the validity of a penalty clause, the validity of a settlement agreement, the assignment of receivables, the assignment of contract, the issue of whether a court has jurisdiction and, generally, any other issue of procedural law, the assumption of debts, the acknowledgement of debts, third-party rights, the p. 1779effects of the contract on third parties, as well as the issue of whether one is jointly liable.
It should be noted that even where all of the positive applicability requirements of a given uniform substantive law convention are met and the matters to be dealt with fall into that convention’s scope of application, resort to private international law may still not be superfluous. This is due to the fact that many uniform substantive law conventions are not mandatory. In other words, many conventions allow the parties involved to opt out of it, but making it necessary to identify the applicable law by means of private international law. As regards the →CISG, the possibility to opt out of it is set forth in art 6, which allows the parties to ‘exclude the application of this Convention or, subject to art 12, derogate from or vary the effect of any of its provisions’. By providing for this possibility, the drafters of the CISG reaffirmed the CISG’s dispositive nature and the central role which →party autonomy plays in international sales. Of course, where the parties exercise their power to exclude the CISG, the applicable substantive rules have to be determined by means of the applicable private international law rules. Similarly, art 5 ILC allows for the exclusion of the ILC, but only if each of the parties to the supply agreement and each of the parties to the leasing agreement agree to it. The IFC, too, allows for its exclusion – but only as a whole (art 3(2)) – by the parties to the international factoring contract or by the parties to the contract for the sale of goods, as regards receivables arising at or after the time when the factor has been given notice in writing of such exclusion. Where the parties take advantage of the autonomy granted to them to exclude the IFC, the applicable substantive rules have to be determined by means of the applicable private international law rules.
From all of the foregoing it clearly follows that it is an oversimplification to state that where uniform substantive law exists resort to private international law is superfluous. Only when there is awareness as to the many limitations of uniform substantive law conventions and, consequently, their non-autarkic character, can one really understand the relationship between these conventions on private international law – which is not an antagonistic one. These uniform substantive law conventions and the rules of private international law necessarily co-exist.
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Franco Ferrari, ‘Forum Shopping Despite International Uniform Contract Law Conventions’ (2002) 51 ICLQ 689;
Franco Ferrari, ‘La Convention de Vienne sur la vente internationale et le droit international privé’ (2006) 27 J.Dr.Int’l 27;
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