Developing a local health plan requires a rigorous methodology and the involvement of all decision-makers and stakeholders, including residents. Corinne Praznoczy, from the Ile-de-France Regional Health Observatory, outlines the process and details the five essential phases: shared assessment, priority setting, action plan, implementation, and evaluation. This approach is essential because the local health plan should serve as the cornerstone of cooperation between cities and the government through regional health agencies.