With air continuing to blow in from the Sahara, a heatwave alert was maintained in a record 67 départements, two-thirds of the country, on Sunday.
Temperatures hit 35-40°C in much of the south and even higher in the towns of Béziers and Chusclan, which sweated in 41.3°C and 40.6°C heat respectively.
The extreme weather did not prevent millions of motorists taking to the motorways, either at the end of July holidays or the beginning of August ones.
A number ended up stranded on the side of the road with overheated engines, while others were caught in traffic jams, one caused by a fire in northern Spain that closed a motorway linking France and Spain.
A smaller fire near Paris disrupted westbound rail traffic, with nine TGV high-speed trains towards Nantes or Bordeaux rerouted and arriving two hours late.
The traffic authority predicted fewer people on the roads on Sunday.
Motorists were not the only people to ignore official advice to stay indoors from 11.00am to 9.00pm and avoid physical strain.
Emergency services in the Rhone valley reported being called out on several occasions, notably having to save an elderly man who was mowing his lawn at 4.00pm.
The weather also meant a rise in ozone pollution, which exacerbates asthma and heart conditions, in the Paris region, Burgundy, the Rhone valley and the Gironde, around Bordeaux.
Two nuclear reactors were closed at Saint Alban, in the south-east, one at Bugey, also in the south-east, and one at Fessenheim, near the German border, to avoid evacuating too much hot water into waterways.
Stéphanie retweets photos of food handed out after her appeal
Vous qui avez reproduis cette initiative et qui distribuez aux 4 coins de Paris et ailleurs en France !! Je vous ❤❤❤🎧 Steph 🚺 (@S_D_V_93) 5 août 2018
Je reçois vos photos 😊 pic.twitter.com/TstKN75uf4
The weather brought a generous streak in some people when two young women, known by their first names, Stéphanie and Dominique, in press reports, appealed for help distributing water and fruit to homeless people.
Stéphanie's tweet was seen by 1.2 million people and she received 1,000 messages of support on Saturday.
Some proposed to copy their initiative elsewhere in the Paris region and in Lyon.While only half a dozen turned out for the first distribution effort on Saturday afternoon, the pair were confident that more would join them for a second effort on Sunday.