The centre of Bobigny saw radical change between the mid-1960s and the 1980s. A municipal team resolutely committed to modern urbanism—districts of tower blocks on elevated slabs—decided on a major urban renewal plan for the old district and the creation of a ‘ZAC’ (joint development zone) on former gardening plots. But in 1965, Bobigny was chosen as the capital for the newly-created department of Seine-Saint-Denis. The departments’s administrative district was then implemented within the municipal ZAC project. It assembles the buildings of the prefecture and of the departmental council, the general treasury and other decentralized State services. This modification to the original plan interfered with the municipal project. But despite extremely critical speeches about the government, the communist municipality supported the project of creating the prefecture on its territory. Bobigny’s new status offered the municipality a chance to consolidate its ambition of becoming the capital city of the department. Three years after the prefecture building was completed, the new town hall was erected. Its architectural choices were in contradiction with the architecture of the prefecture. These two projects, witness of contemporary architecture, thus reflect two competing visions of what places for power should look like in the 1960s-1970s, between triumphant municipal communism and a Gaullist government wishing to bring the administration closer to the citizen.