Metropolitan governance for reindustrialization. Lessons learned from the Lyon chemical valley transformation project. Metropolitan economic development in the era of sustainability transition is bringing out new forms of territorial governance. The article examines their mechanisms based on a case study devoted to the reindustrialization project of the chemical valley in the Lyon metropolitan area. Many lessons about territorial governance have been learned. The first is about territorial characteristics: a local public action targets a space that does not correspond to any jurisdiction perimeter and requires the mobilization of private industrial land. Then, this governance is based on unusual tools: a charter and an innovative call for projects, which frame the public-private partnership and give rise to multiple interactions between industrial owners, external project holders and multiple public actors. An ad hoc "project leader" structure within the metropolitan administration, called Territorial Mission, is delegated the regulation of the game of actors. Far from being on the margins of governance, the State plays an important role, which leads it to reconcile its functions of control authority and industrial development. Finally, this governance is at the service of a reindustrialization which is not reduced to the sole enlargement of the productive and competitive base of the territory. It also aims to ensure the urban existence of industrial facilities, all the more important as some (renewable energies, recycling of materials, phytoremediation) will form the basis of the sustainability transition of the metropolitan territory.