Paris saw a record high temperature of 42.6C (108.7F) on Thursday, amid a heatwave that broke records across Western Europe.
A red alert was issued in north France. Germany also set a new national temperature record of 41.5C - bypassing the figure set just a day before.
The UK recorded a record temperature for July of 38.1C, with trains told to run more slowly to stop rail buckling.
The Netherlands also recorded its highest ever temperature at 40.7C.
"Climate change has increased the likelihood and severity of heatwave episodes across Europe," the UK's national weather service said.