The provisional estimate did not directly link the increased death toll to the heat wave, which led to massive backlogs at morgues and hospitals across France.
While stopping short of tying the deaths to the heat, Health Minister Jean-Francois Mattei said in a statement that "the human drama linked to the heat wave hit the weakest people in our society."
A total of 11,435 more people died from Aug. 1-15 this year — at a time when temperatures rose to 40 degrees Celsius (104 Fahrenheit) in some parts of France — compared to the average over the same span in 2000, 2001 and 2002, ministry spokeswoman Annick Gardies said.
In a related development, French authorities have arrested 34 people -- including 11 minors -- suspected of setting forest fires that ravaged southern France this summer, the Justice Ministry said.
The ministry said 20 of those had already been jailed, either after being convicted or pending investigation. One suspect was cleared and one was sent to a psychiatric hospital. The longest sentence handed down was three years. The remaining suspects have been released, but some could still face prosecution, officials said.
France's center-right government has come under pressure for its handling of the crisis, which came during the summer vacation exodus. Many of the victims were elderly and alone.
Shortly after signs of additional deaths appeared, the government first estimated that 1,600-3,000 people died from heat-related causes starting on Aug. 7. Then, it said a figure of 5,000 was "plausible" died before finally agreeing that an estimate of 10,000 by France's largest undertaker was most probably accurate.
Prime Minister Jean-Pierre Raffarin had warned against giving too much credence to early estimates on the death toll. Full, final figures are not expected until next month.
The heat wave baked many parts of Europe, devastating livestock and fanning forest fires, but no other country has announced a death toll even close to the one recorded by France.
Figures compiled last week by The Associated Press indicated that the heat wave claimed 2,000 lives in countries outside France. Germany, Spain, Britain, the Czech Republic and Austria have refused to extrapolate known heat deaths to estimate a total number.
August is the traditional month for summer vacation in France, and many have accused families of leaving their elderly relatives at home during the heat. Doctors have cited heat stroke and dehydration as often the cause of death.
Several high-level government officials have acknowledged that France was ill-prepared to handle the effects of the heat wave. Air conditioning is not widespread in the country.
President Jacques Chirac has promised that "everything will be done" to correct failings in the health system that was overwhelmed by heat-stricken victims.
On Wednesday, the center-right government floated a proposal to scrap a national holiday and use the tax receipts to finance better health care for the elderly. The main question was which holiday to scrap.