Heat waves are among the most noticeable manifestations of climate change. In France, they are now the deadliest weather events: nearly 36,000 excess deaths were recorded during extreme heat waves between 1974 and 2018. The rapid changes observed in terms of frequency, intensity, and geographic and temporal extent are prompting a reevaluation of public awareness regarding the health risks of heat waves. It is also a matter of encouraging behavioral changes so that everyone can adapt to climate change; reducing the health impact of heat waves cannot be achieved without creating a health-promoting environment and without reducing greenhouse gas emissions.