The fires, which began on Sunday, spread rapidly through the Fontainebleau forest, a UNESCO-designated biosphere reserve, as northern France endured another intense heatwave. The Seine-et-Marne fire department said the burned area exceeded 1,900 hectares by Tuesday morning, adding that the figure was expected to rise as the fires continued to spread.

Paul-Edouard Laurain, spokesperson for the Seine-et-Marne departmental fire and rescue service, said around 850 firefighters were working to contain the fires during the day.

The first blaze expanded quickly, consuming nearly 1,200 hectares by Monday afternoon, according to Interior Minister Laurent Nunez. A second fire later broke out and destroyed about 100 hectares, prompting the evacuation of around 1,000 residents in and around Fontainebleau.

Authorities said one of two people arrested in connection with the fires was an 18-year-old man with no prior criminal record. A source close to the investigation said he was detained with soot on his hands and carrying a lighter.

Officials are investigating whether the fires were deliberately set. Nunez said investigators identified around 10 separate ignition points within a one-kilometer area, a pattern he said suggested the possibility of intentional arson.

The scale of the emergency prompted an unprecedented aerial firefighting response in the greater Paris region. Authorities deployed four Canadair water-bombing aircraft, two Dash planes and three helicopters, with rescue officials reporting 187 aerial water drops during Monday’s operations.

Although firefighting efforts continued overnight with around 600 personnel rotating on the ground, rescue commander Jean-Marc Sicard said weather conditions remained unfavorable and the fire was still advancing despite brief periods of reduced activity.

The wildfires disrupted transport during one of France’s busiest holiday travel periods. Sections of the A6 motorway linking Paris with southeastern France were closed, while railway infrastructure damaged by the fire temporarily halted high-speed train services between Paris and Lyon before repairs allowed operations to resume.

Residents and local farmers joined emergency efforts by transporting water in tractors and making private water supplies available to firefighters. Some homeowners evacuated their properties but later returned to assist rescue crews.

President Emmanuel Macron said all available national resources had been mobilized to combat what he described as an exceptionally large wildfire.

France has experienced its third heatwave in less than three months, with multiple wildfires breaking out across the country in recent weeks. Scientists have linked the increasing frequency and intensity of extreme heat and wildfire conditions to human-induced climate change.

Official figures show more than 2,000 excess deaths were recorded during France’s June heatwave, with a further 300 linked to unusually high temperatures in late May.

Civil security authorities said wildfires have burned about 25,000 hectares across France since the beginning of the year, roughly double the area affected during the same period in 2025. Forecasts indicated high temperatures would persist through Bastille Day celebrations on Tuesday, maintaining elevated wildfire risks across the country.

Interior Minister Laurent Nuñez said investigators had identified around 10 separate points where the fire appeared to have originated within a radius of about one kilometer, suggesting the blaze could have been the result of arson.

“There were about ten points of origin for the fire within a 1,000-meter radius, suggesting it could be a case of arson,” Nuñez told reporters during a visit to Noisy-sur-École in the Seine-et-Marne department. He added that authorities hoped to bring the fire under control later on Monday.

The fire erupted late Sunday afternoon in the Fontainebleau forest, a historic woodland approximately 60 kilometers southeast of Paris. Officials described the blaze as exceptionally intense, with flames spreading rapidly across the forest before aerial firefighting operations were suspended after nightfall.

Around 400 firefighters were deployed to battle the fire, supported by two firefighting aircraft dispatched from southern France, along with two helicopters and an observation aircraft.

Eric Brocardi, of France’s national federation of firefighters, said it was the first time water-bombing aircraft had been deployed from the country’s traditionally fire-prone southern regions to combat a wildfire in the Paris area.

Authorities evacuated about 15 homes in the nearby village of Vaudoué while firefighters worked to protect neighboring communities threatened by the advancing flames.

Residents described hurried evacuations as ash fell from the sky and flames approached residential areas. Valerie, who fled with her husband Daniel, said they loaded their pets into their vehicle after authorities ordered them to leave, adding that fire was visible on both sides of the road as they departed.

Olivier Compta, who is coordinating firefighting operations, said the deployment of aerial firefighting resources helped prevent the evacuation of additional villages.

The wildfire also disrupted transportation across the region. Highways near the affected area experienced traffic restrictions, while France’s national railway operator SNCF reported delays of up to six hours for trains arriving at and departing from Paris’s Gare de Lyon after rail services on the high-speed line toward southeastern France were affected.

The fire broke out just before France’s Bastille Day national holiday and during the first major weekend of the summer vacation season, when travel volumes are typically at their highest.

The Paris region is experiencing its third heatwave since May, with elevated temperatures increasing wildfire risk across much of France. Scientists have said that human-driven climate change has increased both the frequency and intensity of extreme heat events, creating conditions more favorable for large wildfires.

The prolonged heat has affected other sectors as well. French authorities have temporarily shut down three nuclear power stations because of the heat, while organizers of the Tour de France shortened Sunday’s stage by 30 kilometers as temperatures along the route approached 40 degrees Celsius.

Nuñez said forest fires had already burned 17,000 hectares in France this year and estimated that, once all current fires are included, the total area affected would reach about 25,000 hectares—roughly double the area recorded during the same period in 2025.