Introduction: Following the 2003 heat wave, France implemented a national heat wave plan designed to reduce the health impacts of heat waves. The objective of this study is to describe the excess mortality observed during heat waves that have occurred since the plan was implemented. Method: A heat wave is defined as a period during which the minimum and maximum temperatures, averaged over three days, simultaneously reach or exceed departmental alert thresholds. Excess mortality is estimated as the difference between the mortality observed during the heat wave plus the following three days and a reference mortality rate calculated for the same days in previous years. Results: Between 2004 and 2014, 196 heat waves were identified at the departmental level. Excess mortality of less than 10% was observed for the majority of these events. However, excess mortality of nearly 40% was recorded for certain heat waves, and the total impact is significant: 1,562 excess deaths across all periods when thresholds were exceeded, with the majority of these excess deaths occurring in 2006. Conclusion: In the coming years, the increase in heat waves, which seems inevitable, calls for integrating prevention into a broader approach to climate change adaptation.