A major wildfire swept through the Fontainebleau forest, around 60 kilometres southeast of Paris, during France's third heatwave of the year.

Officials said the blaze had burned around 300 hectares by late Sunday and was still spreading.

Hundreds of firefighters, two water-bombing planes, helicopters and an observation aircraft were deployed to tackle the fire.

The blaze disrupted traffic on the A6 motorway and delayed trains from Paris's Gare de Lyon during one of the busiest holiday travel weekends.