A system for monitoring the health impact of heat waves was established following the exceptional heat wave of 2003. It is based primarily on emergency department visits between June 1 and September 15 for hyperthermia, dehydration, or hyponatremia (the iCanicule indicator) among 11 available diagnoses. During the 2023 monitoring period, 16,361 emergency department visits for iCanicule were recorded. Nearly all visits were single-visit cases (98.1%) and were predominantly made in the patients’ region of residence (>90%) except in Corsica (68.6%). Across mainland France, the rate was 24.4 emergency department visits per 100,000 inhabitants, with a marked increase among patients aged 70 and older, and a significantly higher rate among women compared to men (p