France, Aug. 12 -- Seventy-eight departments across mainland France have been placed on orange heatwave alert from midday.

"On Wednesday the heat intensifies further and heatwave conditions continue to gain ground: maximum temperatures will range from 36degC to 39degC in the departments on orange alert," national forecaster Meteo-France said in its 6am bulletin.

Only a sliver of the north-east and a few high-altitude areas will be spared. Meteo France alerts for Wednesday, 12 August.

On Thursday, the number of departments on orange alert will rise to 80, with temperatures above 35degC, and every remaining department on yellow alert as the warning zone extends to the north of the country.

"From the Centre-Val de Loire to Nouvelle-Aquit...