This thesis analyzes two participatory initiatives implemented in the municipality of Ecublens, "Epenex Evolue" and "La Plaine Evolue." Through a qualitative approach combining interviews, field observations, and analysis of strategic documents, the study explores the motivations and interactions between the community social worker, the urban planner, the community police officer, and the project manager, who also serves as the integration delegate. By utilizing the concept of a "boundary object," the research demonstrates how the polysemy of the concept of participation can foster a flexible inter-service dynamic while posing coordination challenges. The results highlight the necessity of collaborative, flexible but rigorous management to sustain more inclusive urban projects and maintain residents' trust.