The blazes have consumed 3,000 hectares (11 square miles) of land along the Mediterranean coast, in the mountainous hinterland and on the island of Corsica -- at the height of the region's holiday season.
France has asked the European Union for help to battle the flames that are still reported to be out of control.
Over 2,000 firefighters and 19 aircraft, including 10 Canadair water bombers, have been mobilised to quench the flames.
With strong winds and tinder dry conditions spelling danger for a second day, the government has asked its European Union partners to send two extra air tankers.
A fire in La Croix-Valmer near Saint-Tropez, a favourite resort with the rich and famous, was still "extremely virulent and difficult to control," the regional head of security Stephane Bouillon told Europe 1 radio on Tuesday morning.
The blaze had already gutted 400 hectares of coastal forest in an area dotted with homes, he said.
In Corsica, scores of firefighters worked through the night to tamp down a wall of flames that threatened homes in the town of Biguglia in the northeast.
The blaze, which consumed 1,500 hectares of forest, engulfed a sawmill and burned several vehicles.
"It's the apocalypse!" a local resident told AFPTV.
By Tuesday morning, the wind had abated and the situation had been brought under control.
In the Luberon, an area of hilltop villages and lavender fields in Provence, fires consumed around 800 hectares around the village of Mirabeau and a neighbouring hamlet.
Around 100 homes had to be evacuated, according to officials, but by Tuesday firefighters had managed to secure residential areas.
Another blaze in Carros, north of Nice, burned a house, three vehicles and a warehouse and led to some homes being evacuated, according to regional authorities.
Speaking to France Info radio, Mayor Charles Scibetta described waking up to a "lunar landscape" and said the inhabitants had had a lucky escape.
"All of France is mobilised," the head of the fire service in southeast France, Colonel Gregory Allione told France Info, adding that extra firefighters had been drafted in from the north.
Southeast France is experiencing an exceptionally hot, dry summer that have made it especially vulnerable to fires.
In mid-July, a blaze believed to have been ignited by a cigarette butt tossed out of a car ripped through 800 hectares of land near Aix-en-Provence.