The author, an official with the Essonne Departmental Directorate of Youth and Sports, presents a program based on the work of Professors Montagner, Restoin, and Testu, which highlights the relationship between daily rhythms and children’s health. Two areas are prioritized: meal-time conditions and digestion, and the design of the spaces dedicated to them (soundproofing, rest areas). The effects of poor physical organization within the school, as well as school schedules, on fatigue levels must also be taken into account. The program incorporates respect for chronobiological rhythms into the organization of children’s various activities, within the framework of a partnership involving schools, students, their parents, all municipal agencies, and community organizations. This results in a city-children-youth contract, covering both school hours and after-school activities (sports, cultural activities, etc.). Training for the adults involved is necessary. The results from the field are briefly presented.