This article presents the process of developing and implementing an intervention project aimed at supporting citizen participation in the organization of adult mental health services. This project took place at a CLSC in Montréal, in the community organization program, in the fall of 2018 and in the winter of 2019. It was conducted in partnership with the citizens of to Montreal neighborhoods, using the adult mental health services, with the members of two committees acting on the basis of citizen representation in the organization of institutional and community services.