Since 2004, France has developed a national plan to anticipate and prevent the health impacts of heat waves (known as the “National Heat Wave Plan” until 2021) as well as a plan to manage the health and social impacts of cold waves (“Extreme Cold Plan”). These plans are coordinated by the Directorate General for Health (DGS) and, as of 2021 for heat waves and 2022 for cold waves, have become interministerial mechanisms in which Santé publique France participates. Since 2023, a new national plan for managing heat waves has been implemented by the Directorate General for Energy and Climate (DGEC). Its purpose is to limit the impacts of heat on the population in terms of organizational aspects (economy, transportation, work, social, cultural, and sporting life), summer comfort, and health. This plan also addresses animal health and welfare. With the goal of streamlining and ensuring consistency, the DGS and the DGEC aim to unify and consolidate all these measures into a single framework dedicated to “extreme temperatures.” This unification would, on the one hand, make the measures more transparent given the great similarity of the current systems, and on the other hand, create beneficial synergy by leveraging the respective strengths of each of these two systems. Santé publique France was consulted by the DGS on June 26, 2025, to review its own surveillance and prevention systems related to heat waves and cold waves and their potential evolution within the framework of the future National Plan for the Preparedness and Management of Extreme Temperatures.