1. The Union’s aim is to promote peace, its values and the well-being of its peoples.
2. The Union shall offer its citizens an area of freedom, security and justice without internal frontiers, in which the free movement of persons is ensured in conjunction with appropriate measures with respect to external border controls, asylum, immigration and the prevention and combating of crime.
3. The Union shall establish an internal market. It shall work for the sustainable development of Europe based on balanced economic growth and price stability, a highly competitive social market economy, aiming at full employment and social progress, and a high level of protection and improvement of the quality of the environment. It shall promote scientific and technological advance.
It shall combat social exclusion and discrimination, and shall promote social justice and protection, equality between women and men, solidarity between generations and protection of the rights of the child.
It shall promote economic, social and territorial cohesion, and solidarity among Member States.
It shall respect its rich cultural and linguistic diversity, and shall ensure that Europe’s cultural heritage is safeguarded and enhanced.
4. The Union shall establish an economic and monetary union whose currency is the euro.
5. In its relations with the wider world, the Union shall uphold and promote its values and interests and contribute to the protection of its citizens. It shall contribute to peace, security, the sustainable development of the Earth, solidarity and mutual respect among peoples, free and fair trade, eradication of poverty and the protection of human rights, in particular the rights of the child, as well as to the strict observance and the development of international law, including respect for the principles of the United Nations Charter.
6. The Union shall pursue its objectives by appropriate means commensurate with the competences which are conferred upon it in the Treaties. (TEU 4; Protocol (No 27) on the internal market and competition)
The Treaty of Lisbon removed the former Article 3(g) from the Treaty establishing the European Community. This provision provided that the activities of the Community included ‘a system ensuring that competition in the internal market is not distorted’. After this provision was removed, ‘Protocol (no 27) on the internal market and competition’ was adopted. In the Protocol, it is stated ‘that the internal market as set out in Article 3 of the Treaty on European Union includes a system ensuring that competition is not distorted’.
1.01 [I]t must be observed that the penalties laid down in Article 15(2) of Regulation No 17 [now Article 23(2) Regulation No 1/2003] in the event of infringement of Articles [101 and 102 TFEU] are a key instrument available to the Commission for ensuring that ‘a system ensuring that competition in the internal market is not distorted’ (Article 3(1)(g) EC [cf. Protocol (no 27) on the internal market and competition]) is established within the Community. That system enables the Community to fulfil its task which consists, by means of the establishment of a common market, in promoting throughout the Community a harmonious, balanced and sustainable development of economic activities and a high degree of competitiveness (Article 2 EC [cf. Art. 3 TEU]). Furthermore, that system is necessary for the adoption, within the Community, of an economic policy conducted in accordance with the principle of an open market economy with free competition (Article [119(1) and (2) TFEU]). […]
General Court 8 October 2008 (Schunk, T-69/04)  ECR II-2567, para. 39.
1.02 […] Article 3(3) TEU states that the European Union is to establish an internal market, which, in accordance with Protocol No 27 on the internal market and competition, annexed to the Treaty of Lisbon (OJ 2010 C 83, p. 309), is to include a system ensuring that competition is not distorted.
CoJ 17 February 2011 (Konkurrensverket v. TeliaSonera Sverige AB, C-52/09)  ECR I-00527, para. 20.
1.03 As to the seriousness of the infringement, the vital nature of the Treaty rules on competition must be recalled, in particular those on State aid, which are the expression of one of the essential tasks with which the European Union is entrusted. At the time of the Court’s assessment of the appropriateness and the amount of the present penalty payment, that vital nature is apparent from Article 3(3) TEU, namely the establishment of an internal market, and from Protocol No 27 on the internal market and competition, which forms an integral part of the Treaties in accordance with Article 51 TEU, and states that the internal market includes a system ensuring that competition is not distorted.
CoJ 17 November 2011 (Commission v. Italian Republic, C-496/09)  ECR I-11483, para. 60.