The Métropole de Lyon to offer an optimal service throughout the territory and for all its inhabitants and users develop digital service platforms “simplifying the life” of citizens. To achieve this objective, the services must be offered independently of the institutions or actors of the territory, and must offer a seamless experience of the city without losing the legibility of the entities delivering the service. Based on the “tell us once” principle, this project addresses the issue of personal data in a holistic approach and correlates the subject of identity management, personal data and their use by third parties, as well as “empowerment” of users.