Projects to install superstructures are systematically exposed to risks of opinion. Among other discursive resources to legitimize them, communication principles of acceptability have been identified. However, they remain insufficiently demonstrated, which limits their scope. This case study contributes to the knowledge of the discursive resources of legitimation, by establishing a link between these practical principles and the conceptual mechanisms that govern the communicational fabric of legitimacy. Also, five (05) years after the completion of this work, we deemed it necessary to revisit the initiatives taken in favor of the people affected by the construction of the interchange have kept their word in the direction of improving and changing conditions. of their standard of living from the angle of communication. This research provides a robust theoretical anchoring to these principles of communication, which will become a real tool for thinking about communication. Among other things, it emerges that oral communication tools are suitable in a context of raising awareness for acceptability and that the participatory approach should not be on the sidelines of a project with a strong social impact for the benefit and in the interest of all. Displaced people around the North interchange.