Strategic planning, transferred to the urban domain at the end of the 80s, has profoundly marked the evolution of spatial and territorial planning, both in the French system, marked by decentralisation at the beginning of the 80s, and in the Italian regional system implemented since the end of the 40s. In France, the SRU law of 2000 introduces the concept of the urban project and new planning instruments, completely remodelling the articulations between the planning scales of agglomerations and communes, introducing more flexibility. In Italy, where the regions have legislative independence in urban planning matters, regional law 36/1997 dissociates the strategic part within the plans from the more programmatic and operational part at the three levels of planning (regional, provincial and communal) and creates new relationships between them. The aim of this research is to verify the role of strategic planning and its relationship with traditional spatial planning, based on comparisons of the exemplary cases of Marseille and Genoa.