Weather forecaster Météo France maintained a heatwave warning for 13 departments on Sunday - Alpes-de-Haute-Provence, Hautes-Alpes, Alpes-Maritimes, the Ardèche, Bouches-du-Rhône, the Drôme, the Gard, the Var, Vaucluse, Hérault, Pyrénées-Orientales and Corsica's two departments, Haute-Corse and Corse-du-Sud.
The thermometer was not expected to drop before 9.00pm on Sunday at the earliest.
On Friday Corsica experienced its second highest temperature ever, 42.7°C in Figari on the south of the Mediterranean island and the southern French city of Montpellier had its highest ever at 37.7°C, while a village in the Alps, Puget-Théniers, hit a regional record at 40.5°C on Tuesday.
857 kilometres of traffic jams
Holidaymakers still headed south on Saturday, as in previous years.
Shortly after midday there were 857 kilometres of traffic jams on the nation's roads, although that had fallen to 440km by 3.00pm.
A heatwave has hit southern Europe this month, with at least five deaths in Italy and Romania attributed to it.
Health authorities in France have warned citizens to be particularly aware of the risks faced by the sick and the elderly, particularly in the light of a 2003 heatwave which resulted in an estimated 15,000 avoidable deaths of pensioners, some of whom had been left on their own by holiday-making relatives.
The heat has contributed to the spread of wildfires that have destroyed thousands of hectares of brush and forest in the south of France and Corsica in the past couple of weeks.
Scientists warn of climate-caused deaths
In research carried out for the European Commission, a group of scientists have warned that the number of deaths caused by extreme weather could increase 50-fold - from 3,000 a year to 152,000 - by 2100.
Heatwaves would account for 99 percent of the deaths, they said in a paper published in The Lancet Planetary Health.
Korean scientists have questioned their conclusions, arguing that humans will develop higher resistance to extreme weather.
Météo France forecaster Frédéric Nathan told the AFP news agency he was sure recent heatwaves reflected global warning.
"We have always had them but their length and intensity has notched up since the 1950s and 60s and they are increasingly coming earlier or later," he commented. "If you look at records for France, the vast majority of new records being set are for high temperatures. Record cold is becoming increasingly rare."