The implementation of national and international objectives for energy transition faces challenges in contexts of urban diffusion. Public actors struggle with the compartmentalization of skills and limited financial resources. In some cases, grassroots movements make the difference. Our aim is to analyze local initiatives and interactions between authorities, professionals, and inhabitants at different scales concerning the modernization of urban networks and services. The goal is to examine new management strategies, bottom-up practices, their relationship with public policies, and the evolution of professional practices. Particularly when municipalities are unable to meet the demand for public facilities in informal urban areas, the development of services shapes the dynamics of urban production and requires the involvement of residents. This contributes to citizens’ political subjectivity and provides them with new forms of sustainable urban citizenship.