The 27-nation bloc has put 12 firefighting planes and a helicopter on standby to assist countries struggling with major blazes this summer.
Meteorologists in France described the situation as "really exceptional" and predicted that a peak of 43 C (109.4 F) could be reached Saturday before thunderstorms bring cooler weather in from the Atlantic.
Experts say the early heat wave is a sign of what's to come as climate change makes extreme temperatures normally seen only in July and August more likely in June too.
