Constitutional change is no longer an obscure and secretive procedure in democracies, as citizens ask for more transparency and take an interest in the very process of drafting constitutional provisions. This study highlights an undeniable movement towards the democratisation of constitutional change processes, which now allows for citizen intervention in all three phases of the reform process: initiative, deliberation and ratification. Indeed, although simple ratification by referendum has become widespread, it is no longer considered by the citizens themselves as a sufficient form of participation in the constituent process. The right of initiative is now one of the main demands of citizens, and new technologies also allow everyone to take part in the debates. The creation of citizens' assemblies can also be a way of opening up the drafting and discussion phase of the proposed constitutional text to ordinary citizens. However, if these assemblies constitute a link between representative and direct democracy, citizens who are not officially invited have in their hands communication tools that allow them to invite themselves in a non-institutionalised way to the constituent process. This freedom to participate, without an established framework, is today the most direct way of contributing to all decision-making processes, complementing representative democracy and institutionalised forms of citizen participation. Moreover, the seriousness of the constituent moment is likely, in practice, to increase the interest of citizens in freely participating in the process. Citizen participation, if carried out under the right conditions, can only enhance the debate and make it easier for citizens to take ownership of the constitutional text that they have directly contributed to shaping. In short, the participation of citizens in the constitutional revision procedure now seems difficult to avoid, even if it is sometimes feared by those in power. In-depth reflection should therefore focus on the establishment of mechanisms and procedures that can both satisfy the desire to involve citizens and the need to respect and consolidate certain fundamental democratic achievements.