France has recorded its highest-ever temperature, hitting a scorching 45.1 degrees as a sweltering summer heatwave grips Europe.

The mercury peaked in the southern town of Villevieille, breaking the country’s previous record of 44.1 degrees during a heat wave in 2003 that killed about 15,000 people.

Up to 4000 French schools were closed in southern France, as the UN warned the hot-house conditions were consistent with climate change and weather bureaus also linked a pattern of extreme heat to global warming.

Cooling off at the Trocadero Fountain in Paris. Photo: Getty

Europe has been in the grip of a heat wave all week, with Germany, Poland and the Czech Republic each recording their highest-ever June temperatures on Wednesday.

Schools have been dousing pupils with water and nursing homes equipping the elderly with hydration sensors to deal with the continent’s record-setting conditions.

In Germany, residents have taken to freezing blocks of ice to use as a cold pack in bed, while in Spain firefighters have been battling Catalonia’s worst forest wildfires in 20 years after a pile of chicken dung spontaneously combusted.

Italy put 16 cities on alert for high temperatures, and civil security services distributed water to tourists visiting famed sites around Rome under a scorching sun.

In France, cooling rooms have been opened in some municipal buildings and mist showers installed on the streets as the country’s weather bureau issued its first-ever heat wave red alert.

Authorities across Europe are urging caution as people undertake risky behaviour to stay cool, such as swimming in dangerous rivers and creeks and illegally opening fire hydrants.

Four people have drowned in France this week and a six-year-old child is in a life-threatening condition after being hit by water shooting from a hydrant in Paris, broadcaster France-Info reported.

Mist showers have been installed on French streets to help residents deal with the extreme heat. Photo: Getty

French Prime Minister Edouard Philippe said the heat wave was “exceptionally intense and exceptionally early” and called on citizens to follow “their sense of responsibility.”

“Heat waves lead to avoidable deaths because the heat, the tension sometimes, makes people take risks,” he warned, adding that the rate of drownings had risen to one per day.

Firefighters in Spain have been battling blazes raging through forests in Catalonia. Photo: Getty

Some criticised the government for going overboard but Mr Philippe defended the efforts after the deadly 2003 event woke France up to the risks.

“Measures have been taken for the most vulnerable people,” he said.

“But given the intensity of the heatwave, it’s the entire population who must be careful today … both for oneself and for loved ones and neighbours.”

Motorway operators have been instructed to distribute water and to provide advice to travellers in French and English for the sake of tourists, Mr Philippe added.

French authorities have planned carefully for hot weather since the 2003 heat wave led to an estimated 70,000 deaths across Europe.

The World Meteorological Organisation said 2019 was on track to be among the world’s hottest years, and that 2015-2019 would then be the hottest five-year period on record.

-with AAP