Meteo France raised the hazardous weather warning to "red," the highest level, for the Marseille and Montpellier areas in southeastern France, forecasting hazardous temperatures of 42-45 degrees Celsius (107-113 F) on Friday.
It was the first red alert Meteo France activated since a four-level weather "vigilance" system was introduced following an estimated 15,000 heat-related deaths in France during a 2003 summer heat wave.
"A heat wave of this amplitude so early in the year, in June, is exceptional," Meteo France meteorologist France Christelle Robert said. "We should expect more intense and frequent heat waves with climate change, because it will accentuate the extremes."
The Italian Health Ministry said seven cities, including Florence, Rome and Turin, already were at Italy's highest heat warning level Thursday. On Friday, 16 cities will be under alerts for high temperatures.
Italian authorities instructed people to avoid being outside during the hottest hours of the day and to stay away from areas with a lot of vehicle traffic to prevent ozone exposure. In France, a red extreme weather warning advises extra precautions for children and older people and cautions that even those in good health are at risk of heat stroke.
Most of the rest of France remained on the next-highest "orange" alert. In Paris and other big cities, including Marseille, authorities banned older cars since high heat exacerbates air pollution. Amid the blistering weather in Europe, hundreds of firefighters struggled to contain a wildfire in northeastern Spain that forced the evacuation of 53 residents.
Firefighters said temperatures over 30 degrees Celsius (86 F), low humidity and high winds fanned the flames. Miquel Buch, the regional interior minister, said authorities suspect the Catalonia region's worst fire in two decades started when the heat caused improperly stored chicken manure to combust at a farm.
In the Czech Republic, where a new June temperature record was set this week, were set this week, gorillas and polar bears at Prague's zoo kept cool by eating their own version of sorbet. Zookeepers have presented the animals with big blocks of frozen water in a form that suits them, and with ingredients to suit their tastes.
The gorillas had two blocks with a mixture of fruits inside, including pieces of orange, apple, pear, kiwi, carrot, pineapple and mango, hanging from ropes in their outdoor enclosure. The zoo's eight Western lowland gorillas stuck to a clear hierarchy. Richard, the dominant male, had a chunk of ice for him own. The other seven have to share one among them all.
The three polar bears get an icy block each. Fish is the main ingredient.