Abstract : This article studies the recentacceleration of the French politics of association of local authorities by the creation of a new level of cooperation, the metropolis. Intended to assure a bettercompetitiveness of the French urban areas, bigmetropolises are the fruit of politicalagreementsnegotiatedbetween the municipalities and the State. Metropolises assure a distribution of the competencies by convention between the variouslevels of territorial powers.