Since 2010 France has strengthened intercommunal cooperation through the creation of metropolises. The new metropolises prolong the development of intercommunality in France by creating groupings with strengthened competences and on broader territories. The present article analyses this change of scale on the basis of the example of the Métropole Aix Marseille Provence (AMP), which covers almost the entire department of the Bouches-du-Rhône and federates 1.8 million inhabitants and 92 communes some of which were old rivals. Its studies the conditions for the development of a shared project on the scale of these new urban complexes based on the construction of Aix Marseille Provence metropolitan development plan. The integration of all the issues and competences into a super intercommunality could lead to an impasse in the case of polycentric urban areas in which the multiplication of institutional arrangements comes to affect the capacity to carry public policies. The lack of political leadership does not allow us to respond to the growing number of arbitrations expected in planning documents. The metropolis is a politically weak institution that has to fight against the injunctions of the State and at the same time emancipate itself from the municipalities that are part of it. While some of the literature has often shown the weight of economic elites and elected officials at these new scales, in this case, the confiscation of power is not where one believes.