Since June 24, around 1,000 more deaths than normal have been registered in the country, according to France's public health authority.
The agency points out that the statistics have not yet been finalised. However, it fears that the number of deaths is on the low side.
It is unclear how many people have died from causes that can be directly linked to the heatwave.
Most deaths have occurred among people aged 65 and older who live alone.
"This reminds us of the need for support and solidarity efforts for isolated people and people living in deep loneliness, even in densely populated areas," the authority writes.
The temperature has eased somewhat in France, after it had been above 40 degrees in many parts of the country in recent days.
