A three-year-old boy died on Wednesday after becoming trapped inside a family car in Saint-Gratien, a suburb north of Paris, as France endured its hottest day since records began in 1947. The public prosecutor in Pontoise said the child had slipped away from his parents, who were resting at home, and locked himself in the vehicle, where he was later found unconscious. Despite resuscitation attempts by his parents and emergency services, he was pronounced dead at the scene. The mother was hospitalised in a state of shock, and an investigation for involuntary manslaughter has been opened.

Across Europe, the heatwave has been linked to a mounting toll of fatalities. In Spain, the Carlos III Health Institute’s mortality monitoring system estimated that 212 deaths between Sunday and Wednesday were associated with the extreme heat, based on statistical excess mortality compared with historical averages. French authorities reported that at least 40 people have drowned since 18 June, many while seeking relief in unsupervised waters, and three further deaths in the Pas-de-Calais region were described by local officials as “likely” caused by the heat. In Italy, the health ministry placed 16 cities under the highest heat alert, while Britain recorded its hottest June day ever at 36.1°C and Germany saw overnight temperatures remain above 26°C in some areas.

The precise circumstances of several incidents remain under investigation. In Carpentras, southern France, two children aged two and four were found dead in a family car on Monday; prosecutors have said they are pursuing the hypothesis of a heat-related death. The Spanish figures represent a statistical estimate rather than individually confirmed cases, and health authorities caution that final attribution of deaths to heat requires further review. The World Health Organization declared the heatwave a health emergency, and the UN climate chief described it as bearing “the fingerprints of the climate crisis,” while scientists pointed to a persistent “omega block” weather pattern that has trapped hot air over western Europe.

Temperatures in Paris reached 40.3°C on Wednesday, the fourth time the capital has exceeded 40°C in 150 years. France’s national thermal indicator averaged 30°C, breaking the previous day’s record. Nuclear power output was reduced as river water used for cooling approached legal temperature limits. Across the continent, schools were closed or hours shortened, outdoor events cancelled, and public health systems placed on high alert. All reported death tolls remain provisional, and investigations into the child’s death and other fatalities are ongoing.