On a warm evening near Bordeaux, a 15-year-old boy flicked a burning cigarette into the trees. Near Perpignan, a 36-year-old man set a paper bag of rubbish alight in roadside bushes. South of La Rochelle, a 50-year-old woman is accused of having lit 17 separate fires. These are not the faces that most people picture when they imagine a summer of catastrophic wildfires — yet since the season began, French authorities have arrested 514 people on suspicion of arson, 198 of them minors.

The scale of destruction has forced France to confront an uncomfortable set of statistics. According to the French interior ministry, a record 115,000 hectares of forest, scrubland and heath have burned in a single summer. Official data show that nine out of every ten wildfires in the country are caused by human activity, with roughly two-thirds classified as involuntary — a barbecue left unattended, a spark from a machine, a carelessly discarded cigarette. That still leaves one third set with deliberate intent.

In 2025, arson was the single largest identified cause of forest fires in France, responsible for 29.4 percent of all blazes recorded. Understanding who commits these acts, and why, has proved elusive. "These are often crimes that are unsolved, or don't lead to convictions, because the fire has destroyed the evidence," said Thierry Toutin, a criminology researcher with the French national police.

Arsonists, he has written, have "many different profiles," and the field remains deeply under-studied.