Swimming pools and parks will remain open at night and special “cool rooms” are being set up in municipal buildings.

The measures aim to avoid a repeat of an emergency in 2003 when thousands died and mortuaries in the French capital ran out of space.

France is bracing itself for temperatures expected to exceed 40C later this week, potentially breaking all records. High humidity in the Paris region could make 40C feel like 47C.

A continental heatwave is also set to test the resources of public authorities in Germany, Switzerland and Belgium. Spain’s weather agency is predicting temperatures of 42C in the Ebro, Tajo, Guadiana and Guadalquivir valleys.

The city of Paris has activated “level three” of its plans for extreme heat – just one below the level four maximum that has never been reached. 

The plans are borne of the trauma caused 15 years ago by the deaths of 15,000 people as soaring temperatures hit 44C.

Mayor Anne Hidalgo said large swimming pools would stay open and free temporary outdoor pools would be set up in dense, low-income areas.

The plan includes the establishment of temporary fountains and a care strategy for vulnerable people, including the elderly. Water is to be distributed to the city’s growing population of rough sleepers, including a large number of migrants living in tents.

Authorities have designated about 900 “cool places” where temperatures are lower than the surrounding streets, such as air-conditioned public buildings. 

Hospitals are bracing for an influx of patients even though there has been strike action recently over budget cuts.

Paris has few green spaces and city officials have been trying to establish more more trees and plants to counter the heat that is retained by its buildings, stone and concrete.

The extreme weather has inevitably been linked by many observers to global heating caused by climate change, with temperatures across Europe reaching unforeseen highs.