A forest fire in the south of France has revealed a cache of 400 historic shells and munitions in the village of Le Porge, according to local authorities.

Blasts, initially thought to be exploding gas cylinders, may have been World War Two explosives detonated by the heat of the fires, the local fire commander told local media.

More than 100 explosions were heard on the second night of the fire, Mayor Martial Zaninetti told French news outlet France Info, likening it to "the sound of war".

Demining operations have now seen most residents return to their homes, however the mayor has said certain areas are still off-limits. More than 180 houses in the area were destroyed by the wildfire.

"There were ammunition depots buried in land within our municipality, but we didn't know it, and they exploded", Zaninetti told France Info.

He described them going "to the right, to the left" and that there was "even one that went through a house".

In a statement on Instagram on Monday, the mayor wrote that access to the ocean, a campsite, and the village of La Jenny remained off limits.

The historic weapons were both German and French and included mortar shells and anti-tank shells, French media reported.

Their discovery comes after a forest fire ravaged the Gironde area, which has now been brought under control after burning for about 10 days.

Pictures from Le Porge on Monday showed families picking through the burned remains of their homes.

On Monday, French Prime Minister Sébastien Lecornu thanked firefighters for their efforts saying "France has stood firm in the face of an unprecedented crisis".

He highlighted the battle against the fires had entered a "new phase" in the Gironde region, saying "the evacuated individuals are gradually returning to their homes".

Wildfires have raged across Europe over the two weeks, primarily in France and Spain, where more than 330,000 people were evacuated.

France was one of the worst affected regions, with an area of 42,000 hectares burnt in the south-west, making it one of the largest forest fires since World War Two.