Those plans will be put to the test this week, when temperatures across Europe are expected to rise above normal as hot air from deserts in Spain and the Sahara blows northward.
Temperatures in Germany on Wednesday could smash the existing June record of around 38.3C set in Frankfurt in 1947, meteorologists warned. The heat wave is also expected to hit Belgium and Switzerland, and some parts of Sweden and Denmark could see unusually hot days as well.
But the memory of the deadly summer of 2003 weighs most heavily on France, and authorities there have already begun to implement emergency plans.
In France, temperatures from Wednesday through Friday could climb beyond 38C. Paris has issued an orange alert - it's second-highest heat warning - for the city and surrounding area.
Authorities announced a number of measures to keep residents cool, including installing temporary water fountains and three portable pools in high-density neighbourhoods, keeping swimming pools open until 10.30pm and even permitting residents to swim in the basin of the Canal de la Villette in northern Paris.
On Monday, Paris Mayor Anne Hidalgo told Le Journal du Dimanche that 13 large parks will remain open overnight until at least Tuesday next week, and the city is distributing 5000 water bottles to the homeless.
The city is also improvising misting devices out of fire hydrants and setting up more than 900 "cooling rooms" for residents. The new la Chappelle shelter for migrants will remain open all week and provide 400 showers per day, Hidalgo said.
"We are ready," she told JDD.
The heat particularly threatens children, pregnant women and the elderly, city authorities warn. The city has set up a special phone service for elderly and sick people, and authorities have asked hospitals and retirement homes to be on alert. Older residents left alone made up many of the victims of the 2003 heat crisis.
"As you know, at times like these, sick people, pregnant women, infants and elderly people are the most vulnerable," French President Emmanuel Macron said yesterday. "So we must be vigilant with them and have prevention measures in place in order to intervene as quickly as possible."
A poster circulated by the regional health agency for Paris warns all residents to drink plenty of water, to refrain from consuming alcohol and to "wet the body" frequently.
Parisians already appear to be heeding the advice. Kids splashed in the Trocadéro fountains by the Eiffel Tower today to cool off, and technology stores in Paris offered special sales on fans.
Intermediate school students are also getting an unexpected reprieve from national exams scheduled for June 27 and 28. The exams, which determine whether students pass the equivalent of the ninth grade, have been postponed until the following week due to the heat, national education minister Jean-Michel Blanquer announced.