The emergence of new participatory mechanisms, such as participatory budgeting, in towns and cities in recent years has given rise to a conflict between the old protagonists of local participation and the new citizens invited to participate. These mechanisms offer a logic of collective action different from what has been the usual fare in cities — one based on proposal rather than demand. As a result, urban social movements need to transform their own dynamics in order to make room for a new political subject (the citizenry and the non-organized participant) and to act upon a stage where deliberative dynamics now apply. This article aims to analyse this conflict in three different cities that set up participatory budgeting at different times: Porto Alegre, Cordova and Paris. The associations in the three cities took up a position against the new participatory mechanisms and demanded a bigger role in the political arena. Through a piece of ethnographic research, we shall see that the responses of the agents involved (politicians, associations and citizens) in the three cities share some arguments, although the conflict was resolved differently in each of them. The article concludes with reflections on the consequences this conflict could have for contemporary political theory, especially with respect to the role of associations in the processes of democratization and the setting forth of a new way of doing politics by means of deliberative procedures.