At least 18 people have died amid a deadly heatwave in France, including children found in cars, as authorities across Europe issue warnings.

Records were forecast to be shattered across swathes of France, with Bordeaux, in the southwest, expected to exceed 42 degrees on Monday (local time).

Almost 2700 French schools were set to close or modify timetables and 49 regional administrative areas were under a red heatwave warning.

Cooling off in the Canal Saint-Martin amid a heatwave in Paris. Photo: AAP

Earlier, alcohol consumption was banned in public places across France for a national music festival, Fête de la Musique, amid fears for people’s health.

French Health Minister Stephanie Rist warned: “We don’t know when temperatures will start falling.”

“We’re heading for, at the very least, several days of very, very hot weather.”

Spain’s normally cooler north Basque region was bracing for 40-degree heat that was more than double its historic average for June 22, according to the Reuters Climate Monitor.

San Sebastian would be hotter than the southern cities of Seville and Cordoba, which normally record Spain’s most intense summer heat.

Tourists and Parisians cool off near the Eiffel Tower. Photo: AAP

“We are seeing temperatures between five and 10 degrees above normal for this time of ⁠year, and in some northern areas even more than 10 degrees above average,” Aemet spokesman ‌Ruben del Campo said.

The night was providing little relief in some parts of Spain, with temperatures failing to drop below 25 degrees or even 30 degrees in places ​like the southwestern ‌province of Almeria, Aemet said.

Reuters reported at least 18 deaths linked to the scorching temperatures.

Two children, aged four and two, were found dead in their family’s car in south-eastern France.

Three elderly people, aged between 80 and 95, died at the weekend in the ‌Bordeaux region.

Wildlife shelters in northern Europe were struggling to cope with the number of animals being brought in suffering from the heat.

Birds such as swifts, swallows, sparrows ​and ​starlings, which make their nests in the eaves of roofs, have ​been particularly affected by abnormally high temperatures, said Romaine de Jaegere, founder of the Centre for the Rehabilitation of Animals Living in the Wild (Creaves).

“Temperatures on the roofs can sometimes reach 50, even 60 degrees Celsius. So they prefer to jump rather than let themselves die and literally cook in their nests.”

Europe on Monday was the continent furthest from its historic norm, with an average high temperature of 24C, which was 4.1C above ​what was typical from 1961 to 1990, according to the climate monitor.

By comparison, Asia and North America were 2C and 1.3C above the historic norm.

Spain’s Labour Ministry on Monday said it was monitoring whether companies were complying with laws that allowed workers to reduce or adjust their ​hours when orange or red weather alerts are issued.

Workers are also entitled to up to four days of paid leave if they are unable ​to reach their workplace due to weather conditions, ⁠it said.

-with AAP