The Marseilles-Aix metropolitan region developed in a geographic location which conditioned its urban organisation. This Mediterranean littoral territory is structured by coastal mountains (massif Cassis la Ciotat, Calanques, Côte Bleue), fragile humid spaces (Etang de Berre, Camargue) and a river (the Rhône and its tributary, La Durance). The littoral land itself has constraints: the mountain amphitheatre of Marseilles commune, Alpilles and Lubéron. All these elements have imposed the circulation corridors and influenced the urbanisation processes.
A Marseilles metropolitan planning scheme was elaborated in the late 1960s and early 1970s by local representatives of the central state in consultation with the communes. This scheme was used by the central state to coordinate its major investments in the urban region. It has also had a major influence on the urbanisation processes in this urban area since the 1970s, mainly through the highway system. No metropolitan strategy has been elaborated since the 1970s. The decentralisation process during the 1980s and 1990s developed competition between communes. The local institutional culture is historically one of autonomy and non-cooperation 1 between communes. Since 1990 the central state, using the institutional national reforms (1992 and 1999-2000), and by specific policies, has worked on the emergence of metropolitan policies in the Marseilles-Aix urban region. What should be acknowledged first is the fundamental role of the central state and its representatives in the urban region. This role is not a role of imposition of policies. Since the beginning of the decentralisation reforms of the 1980s the central state has been encouraging local public institutions (Commune, Département, Région) to volunteer (Duran and Thoenig, 1996) for new policies.
How has it been possible for the territorial public institutions to cooperate more and more during the 1990s? What has been the precise role of the central state and its representatives? Has it be done specifically by national reforms? Have any metropolitan policies developed? A further aim of this case study is to