It exceeded previous records set during heatwaves in August 2003 and July 2006.
Meteo-France added that this month was also the third driest July in history – precipitation was almost 70% below average, leading to soil drying and increased risk of forest fires.
This year, Europe has been hit by successive heatwaves and severe droughts, which scientists attribute to human-induced climate change.
Due to heatwaves continuing in France since May, worsening conditions last month contributed to the largest forest fire spread in the country since 1949.
The fire that broke out on July 22 burned 42 thousand hectares – an area four times larger than Paris.