This thesis of doctorate is about the communication in the urban projects. She is found on the international diffusion of the project logic as norm to make and to arrange the city. Diffusion that drive us to examine the communicational practice that the project allow. The norm project, today shared, does it imply some similarity in terms of communication? In a multipartenarial context, how does he organize the meeting apparatus? Until what point does to make the city imply him the involvement of the inhabitants? What are the issues of the communication that go with project? Two fields have been mobilized in a comparative perspective; the urban shutter of the Contract Getting out of Debt Contract Development (C2D) of Douala and the Big Urban Project (GPU) of Lille. 33 interviews, non participant observation, working papers and a significant corpus of press served to support a conceptual armature resting on the notions of apparatus and communication activity. The main results show a strong salience of communicational dissimilarity in the studied projects. These differences must be put in perspective with specific institutional contexts. Indeed, the communication in the C2D of Douala is minimal, implemented by internal actors to the Urban Community of Douala, but external to the team of project. In the case of the GPU, the implementation of the communication leans on outside operators to the project team, although the communicational activity is drived by the members of the aforesaid team. The place of the inhabitants deal to see a minimal involvement of the Douala casa whereas. In the Big Urban Project of Lille, we see an active continuum of the simple consultation to the coproduction of some facilities. Finally the accompaniment communication includes a strongsymbolic dimension in Lille whereas in Douala, it limits herself to evenementialisation who deserve of the Government Delegate close to the Douala Urban City Council.