This article focuses on the experiment in communalist direct democracy that took place in Commercy, France, from the beginning of the gilets jaunes (yellow vests) movement, to the project of putting forward a list of candidates in the 2020 municipal elections. The article begins by narrating this experiment to show how participants imagine the ideal of giving power to the assembled people, and to describe the concrete experimental forms they create to this end. After analyzing the ways in which this movement reinvents representation, the article explores the constitutional issues encountered by the actors in their reflections on the institutionalization of the assembly. Indeed, this process raises a fundamental question for any constituent power: its legitimacy to institutionalize a new democratic system. Through this experiment, the aim is to understand how the constituent paradox can be thought through, and resolved by, a communalist direct democracy movement.