At the end of a week of confusing weather, going from heavy rain to scorching heat, official weather-watcher Météo France predicted summer storms in large parts of the country on Friday night.
Temperatures soared on Thursday to above the seasonal average, approaching 40°C in Aquitaine in the west of the country, and continued to rise on Friday with Paris and central France hottest at about 36°C.
But the brilliant sunshine is not expected to last.
Heavy storms are forecast to hit western France on Friday evening, travelling east overnight and hitting a belt of the country stretching from Picardy and Paris to Languedoc and the Pyrenees.
Winds could reach 100km per hour in some parts of the country.