More than 11,000 people have been forced to leave France's south-western Gironde region in the past few days.
Dozens of fires are burning in Portugal and Spain where temperatures have surged above 40C.
At least 281 deaths in both countries were linked to the heat and several towns in western Spain were evacuated.
Portuguese villagers were also told to flee when flames crossed the border from Spain.
The head of France's firefighters' federation has warned of the impact global warming is having on civil protection. "It's firefighters, civil security who deal with the effects on a daily basis - and these effects aren't in 2030, they're right now," said Grégory Allione.
Heatwaves have become more frequent, more intense, and last longer because of human-induced climate change. The world has already warmed by about 1.1C since the industrial era began and temperatures will keep rising unless governments around the world make steep cuts to emissions.
Firefighters in Spain fought to protect the town of Monsagro as fires erupted further south in the Monfragüe national park, home to rare species of birds. The main N-5 route in Cáceres just east of the park was cut off when a forest fire reached the road.
In Portugal, 47C was recorded at Pinhão in the north on Thursday, a record high for July in mainland Portugal.
The Carlos III Health Institute said on Thursday that at least 43 people had died during the first two days of the latest heatwave, on Sunday and Monday, because of the heat.
Health officials in Portugal recorded 238 deaths more than normal since 7 July which they attributed to the very hot and very dry conditions. The worst affected are the elderly, children and people with chronic diseases. Emergency officials said 187 had been injured because of the fires in the past week.
More than 30 fires were active in Portugal on Friday, including one in a forest at Pombal in the central region of Leiria which has lasted a week. More than 300 sq km have been torched this year, a bigger area than in all of 2021.
The EU's Copernicus emergency management service tweeted a map showing the biggest fire risks across Southern Europe and Morocco.