Firefighters tackle the blaze on the outskirts of Marseille
Foreign legionnaires in the French army have been strongly criticised for starting a forest fire which spread to the outskirts of Marseille.
Seven firemen and police were hurt, and hundreds of people fled their homes.
French Prime Minister Francois Fillon, viewing the devastation, said clear instructions had not been followed and the mistake was "inexcusable".
The officer in charge when soldiers fired tracer bullets during a training exercise has been suspended.
The firing of the bullets went against regulations.
It was the second time in two years that the military had started a wildfire.
Mr Fillon said: "Everyone knows among the soldiers who use the camp that tracer bullets are banned.
"There are very clear instructions and regular work is done with the ranks to remind them of the rules. It is a mistake that no explanation can excuse."
Defence Minister Herve Morin added: "On this occasion we have got an NCO who... has not obeyed instructions. This is all appalling."
The blaze threatened some 400 homes and elderly residents had to be evacuated.
The fire reached the outskirts of Marseille
Inhabitants of a retirement home in La Panouse, south of Marseille, had to be carried away in their pyjamas in the early hours of the morning.
A nearby centre for the disabled was also cleared as the fire approached.
By Thursday morning, rescue workers said it had been brought under control, although some 500 firefighters remained at the scene.
Marseille's mayor and senator, Jean-Claude Gaudin, demanded that the military help out with the clean-up operation.
"Personally, I can't see the need to carry out military exercises in 32-degree heat and a strong wind. It must really have been someone who is not from around here who took this decision," he said.
"We did the best we can but when you're faced with this kind of incredible stupidity, you need to say so with a certain force."
Strong winds and high temperatures have helped trigger fires across the region.
In Spain, the high-speed rail link between Madrid and Barcelona was suspended because of blazes in the north-east of the country.
Four firefighters were killed in Tarragona province on Wednesday, and another on Thursday, while more than 1,000 people were evacuated from their homes.