Through the Let's Food Cities project, Let's Food association aims to encourage cities to transition towards more sustainable food systems, by fostering cooperation and echanges of good practices between cities. Initiatives such as the Milan Urban Food Policy Pact are providing a framework for cities to exchange and cooperate on food. Let’s Food Cities aims at operationalizing these exhanges, by using the strong tool of decentralized cooperation mechanisms in France, to foster cooperation between French cities and their existing twin cities, on food and agriculture. 7 French cities are signatories of the Milan Urban Food Policy Pact, 7 couples of cities are then the focus of this study: the French city, and its twin in Asia, Africa or Latin America. To encourage and facilitate this cooperation, 2 tools are built: an assessment of the food system's sustainability of the 14 cities, and an interactive web tool "resources center" where are shared technical, financial and technological innovations cities can get inspired from.