Our research project: to build local economic sectors to human food, respectful of the environment and people, at a good price, and with a fair and equitable income for each actor. The example chosen is the construction of a short circuit for the marketing of Polenta semolina, ranging from the selection of a high quality maize variety adapted to the Ile de France, its processing, and its direct sale, including canteens. The model could then be applied to other products.