In a few years, the term "metropolis," which until then had been used only by a small circle of political, administrative and academic actors, has entered the everyday language. It is now used by a variety of citizens, elected officials and journalists, as well as by social movements that politicize and challenge metropolitanisation. For these movements, the "metropolises" are both the beneficiaries of contemporary socio-spatial transformations and the cause of new territorial and social fractures. This special issue focuses on the various forms of contestation to which metropolises are subjected to - a variety that arguably reflects the multiple facets of the metropolitanisation process. The papers gathered in this issue advance multiple hypotheses and avenues for research on the adaptation of forms and repertoires of mobilisation to the characteristics of metropolitanisation; the cognitive and discursive resources provided by metropolitan semantics and imaginaries for universalising the cause of movements; the socially selective attributes of the main actors involved; the role of political opportunity structures that contribute to the metropolitan re-scaling of social movements in France; and finally, the relations between metropolitan social movements and metropolitan politics.