(BSS/AFP) - France braced for the hottest day yet in its latest heatwave on Monday, with temperatures that could climb up to 43C in the west of the country and hundreds of schools closed.

In a first, France`s highest heat warning was issued across half the country for Monday, with forecasters warning the scorching weather could end up being as serious as a 2003 heatwave that claimed the lives of nearly 15,000 people nationwide.

Monday afternoon could see temperatures rise to 43C (109F) in the southwestern city of Bordeaux and 39C in Paris, according to weather service Meteo-France.

More than 800 of the country`s 60,000 schools were to be closed, while 1,800 others were to adjust teaching hours, the education ministry said.

Since last week, other schools have suggested that parents keep their children at home or pick them up at lunchtime to extract them from boiling classrooms.

A primary school teacher in the Bordeaux region, who asked to remain anonymous to speak freely, told AFP she was alarmed that the authorities were not taking measures to cool down schools.

"Last week, it was 32C in the classroom for the children.

"It`s only going to get worse, while the supermarket across the street is cool and air-conditioned," she said.

"Everyone thinks it`s normal but one day we`re going to end up teaching in the aisles of the supermarket."

- Global warming -

On Monday morning, the Paris regional authorities urged residents to stay at home, warning disruptions were expected on public transport.

"Our transportation system is going to suffer enormously... because the rails can`t withstand temperatures above 50C," head of the Paris region Valerie Pecresse said.

Air conditioning inside the carriages would also not be sufficient for trains packed full during a "rush hour at 40C", she added.

France is experiencing its second heatwave this year after an unusually hot spell in May that shattered records across half the country.

Scientists have shown that recurring heatwaves are a clear marker of global warming, primarily caused by burning coal, oil and gas -- and warn they are set to become more frequent, longer and more intense.

Meteo-France says that of the 51 heatwaves recorded nationwide since 1947, 34 have occurred since 2000 and 26 since 2011.

The exceptional temperatures experienced in 2003 in France, Italy, Portugal and Spain led to tens of thousands of deaths.

Scientific studies estimate more than 70,000 people died across 16 countries.