This thesis examines the contemporary modalities of coordination and legitimation of public action within the framework of urban projects, based on an analysis of the Centre sécurité de la rade (CSR) project in Geneva. Situated within the shift from plan-led urbanism, grounded in technocratic and centralized rationality, to project-based urbanism characterized by negotiation, flexibility, and the management of uncertainty, the study draws on theoretical contributions related to urban projects, urban governance, and the legitimacy of public action.

The research is based on a case study that highlights the role of the urban project as an instrument for coordinating actors and as a space of political production, within which compromises are constructed between divergent institutional, sectoral, and territorial interests. In the Geneva context, the project emerges as a central device for articulating resources, justificatory frameworks, and power relations among actors.

Finally, the thesis demonstrates that the legitimacy of public action is no longer founded exclusively on hierarchical authority or technical expertise, but is instead constructed in a procedural manner, through the administration’s capacity to steer collective action, organize negotiation processes, and produce overall coherence under conditions of uncertainty.