France is battling a "monster" wildfire raging for a third day near the wine-growing heartland of Bordeaux, with no let-up in blistering temperatures likely before the weekend.

More than 1,000 firefighters backed by water-bombing aircraft tried to contain the blaze in the southwestern Gironde region that has forced thousands of people from their homes, scorched 6,800 hectares of forest and destroyed houses.

"It's an ogre, it's a monster," Gregory Allione from the French firefighters body FNSPF told RTL radio.

Wildfires have broken out across Europe this summer as successive heatwaves bake the continent and renew focus on climate change risks to industry and livelihoods.

Firefighters said they had managed to save the village of Belin-Beliet, transformed into a ghost town after police told residents to evacuate as the flames approached.

The ruins of a house destroyed by the fire in Belin-Beliet

But the blaze reached the outskirts, leaving wrecked houses and charred tractors in its wake.

"We've been lucky. Our houses were saved. But you see the catastrophe all over there. Some houses could not be saved," said resident Gaetan, pointing to houses burnt to the ground.

"The fire arrived very violently and quickly in this area," said lieutenant colonel Arnaud Mendousse, a Gironde firefighter.

Juliette Pilain, a 19-year-old student, was evacuated from Belin-Beliet yesterday.

"I took two-three pieces of clothing, my ID papers, I had to leave my cat. They were closing the roads. But the volunteers said they would continue to leave water out for the animals."

'We're heartbroken'

President Emmanuel Macron said European countries were coming to France's rescue. Two Greek tanker planes were arriving alongside two Swedish air tractors, 64 firefighters from Germany, 146 from Poland and more from Austria and Romania, his office added.

More than 57,680 hectares have gone up in flames so far in France this year, nearly six times the full-year average for 2006-2021, data from the European Forest Fire Information System shows.

French authorities said temperatures in the Gironde region would reach 40C today and stay high until Saturday.

Firefighters warned of an "explosive cocktail" of weather conditions with wind and the tinder-box conditions helping fan the flames.

The Gironde was hit by big wildfires in July which destroyed more than 20,000 hectares of forest and temporarily forced almost 40,000 people from their homes.

Hostens mayor Jean-Louis Dartiailh described the past weeks as a disaster.

"The area is totally disfigured. We're heartbroken, we're exhausted," he told Radio Classique. "(This fire) is the final straw."