France, June 22 -- At least 845 schools will be closed, French Education Minister Edouard Geffray said on Sunday, while around 1,800 will cut classes short.

Most of those affected are in the 49 departments where France's national weather service has declared a maximum "red alert" for extreme heat, including the entire Paris region, all of the west coast and swathes of the centre and south.

It represents France's most extensive red alert to date. Another 40 departments are on the second-highest alert level.

Meteo France has cautioned that Monday could be "among the hottest days ever recorded across France", with temperatures forecast to climb as high as 41C.

"Monday and Tuesday are likely to be very hot. We are likely to break temperat...