This contribution aims at analysing the history of the inclusion of values and principles in the European Treaties from the 1951 ECSC Treaty to the 2007 Lisbon Treaty and beyond. It will specifically focus on the evolution of values and principles that enable EU citizens to participate in democratic processes and EU policymaking. Going beyond the ECI, the contribution will examine and assess how citizens and citizens’ representative associations were given the possibility to exchange views in areas of EU action, how a transparent and permanent dialogue between the institutions and representative organisations is established and maintained, and how the consultation mechanism is built and used. The contribution relies on text analysis and literature review as well as on the analysis of the legal framework and policy developments in view of an increasing need for participatory democracy of citizens in the EU.