While the French government entered into many climate-related commitments since the early 2000, the current climatic change urges lots of actors to commit themselves, among which local authorities. If neither the State nor the legislation give them much clear help or direction, many mayors decided to get hold of the climate change stake, some of them in an opportunist way, and many of them with sincerity.Choosing the way of mitigation rather than adaptation, French local authorities have been, for some years, finding out some new decision and action models, including more participation of the inhabitants and local stakeholders. In the same time, some new ways of life and new urban shapes are locally emerging, collective-oriented more than individualistic as the standard used to be for some decades.