To voice their opposition to the Comprehensive Economic and Trade Agreement (CETA) and the Transatlantic Trade and Investment Partnership (TTIP), and try to put an end to their negotiation or impede their conclusion, a group of citizens, supported by civil society organizations used the European citizens’ initiative (ECI) mechanism. This ‘Stop TTIP’ initiative was denied registration. This rebuttal was contested before the General Court, leading to its annulment in the Efler decision. The first use of an ECI in the context of free trade agreement (FTA) negotiation raises the question whether it can be a valuable political tool for citizens to exercise an influence on this domain. To answer this question, this chapter compares the ECI regulation and the legal framework of the EU’s FTAs negotiation and implementation and relies on the Tribunal’s Efler ruling. It concludes that if the ECI has a wide scope to be used in FTAs’ negotiation and implementation, the real influence it will provide citizens is uncertain and depends on civil society, the institutions and subsequent rulings.