Declaring the fire 'contained' on Tuesday evening, the local préfet warned that the fires were not extinguished and firefighters will need to remain on the scene for days, if not weeks.
Four people remained in custody on suspicion of deliberately starting the fires, including a volunteer firefighter, prosecutors said.
The Fontainebleau fire is far from the only wildfire ravaging the French countryside - on Wednesday morning 19 fires were in progress, according to the government's Feux de Forêt app, ranging from the south coast to Brittany.
Météo France has declared 36 départements at 'elevated' risk of wildfire due to a combination of weather conditions and parched vegetation. However the number is set to fall from Thursday as temperatures are predicted to cool.
READ ALSO: MAP: How to get the latest wildfire information and alerts in France
The Fontainebleau fires, which erupted during another fierce heatwave that has left France sweltering, have seen three giant Canadair aircraft scoop up water from the Seine river to douse the flames.
The smell of burning was even reported up to 100 kilometres away near the city of Orleans, AFP reporters said.
Interior Minister Laurent Nunez said there had been nearly 300 water drops in 48 hours. "The aerial resources played a decisive role in bringing these fires under control," he wrote on X.
Fontainebleau forest, around 60 kilometres southeast of Paris, is a sprawling former royal hunting ground that draws hikers, nature lovers and climbers who come to tackle its famous boulders.
It covers some 25,000 hectares (62,000 acres) and is visited by more than 15 million people every year. Its popularity, plus sandy soil and vegetation including ferns and highly flammable conifers, makes it vulnerable to fire.
In all, six people have been arrested as part of the investigation into the wildfires, which forced about 1,000 local residents from their homes and shut the main A6 motorway from Paris to the southeast.
The volunteer firefighter admitted having "set fire to twigs with a lighter and gasoline" while another man acknowledged "accidentally starting a fire by throwing his cigarette", Fontainebleau public prosecutor Diane Ngomsik said.
The Seine-et-Marne Departmental Fire and Rescue Service said the firefighter has been suspended, and expressed its "deepest dismay".
The fires, which mobilised more than 800 firefighters, have scorched around 2,050 hectares -- an area roughly three times the size of Gibraltar, authorities said.
Charred trees and soot-covered ground have been left in the landscape of outstanding natural beauty. Small fires have reignited as winds fan the flames back to life.
Hopes rose throughout the day that the A6 may reopen on Wednesday but officials still urged caution until the fire was stabilised.
The prefect of the Seine-et-Marne region, Pierre Ory, said those who had to leave will be able to return home but not before Wednesday.
"Contained means they (the fires) are confined within their perimeter" but not "extinguished", he told reporters.
Nunez said 32,000 hectares across France have been hit by fires since the beginning of the year -- more than during the entire 2025 fire season.
As well as the warmer south, fires have also hit cooler regions such as Brittany in the west, where a fire that swept across 38 hectares of heathland on Cap Frehel has now been brought under control.
Comments