How Specialists Determine the Causes of Wildfires in France

Bordeaux – 24 July 2026: According to Interior Minister Laurent Nuñez, 128 people have been arrested in France on suspicion of having started forest or vegetation fires. However, the figure cited by the minister during a visit to Gironde on 22 July does not constitute proof of guilt. Above all, it points to the rapid forensic and police work carried out after a fire.

At the center of the process is the so-called RCCI, the unit responsible for investigating fire causes and fire progression. Such teams are deployed during ongoing fires or fires that have just been brought under control. Their first task is not to identify a perpetrator, but to narrow down the suspected point where the fire started and reconstruct its course as precisely as possible.

The RCCI brings together different areas of expertise: firefighters analyze fire dynamics, gendarmes secure evidence and carry out forensic measures, while staff from the national forestry office assess vegetation, terrain and weather conditions. In major or complex incidents, specialists from the Gendarmerie’s Criminal Research Institute may also be called in. Their work often begins only a few hours after firefighting operations have ended.

Crucial to the work is a backward-looking analysis of the fire pattern. Burned grasses, the orientation of damaged trunks, soot marks or even the position of a charred snail shell can indicate the direction in which the flames moved. This makes it possible to gradually narrow the search to the fire’s original point of origin. Areas that are particularly badly burned are not necessarily where the fire began.

Only after this technical reconstruction does the actual criminal-law assessment begin. Investigators must determine whether a fire was caused by negligence, a technical defect, professional activity, natural causes or an intentional act. Witness statements, video footage, telephone and vehicle data, and laboratory analyses can supplement the evidence secured at the scene. Arrests therefore do not automatically mean responsibility can be proven in court.

The importance of these investigations is growing amid an exceptionally severe fire season. Since the start of the year, more than 12,500 fire outbreaks have been recorded in France, according to recent media reports; around 44,000 hectares are believed to have already burned. This would make the area affected so far larger than during the whole of 2025. Authorities view the combination of drought, high temperatures and wind as a major factor intensifying the risk.

According to the Gendarmerie, around nine out of ten fire outbreaks are linked to human activity, including both deliberate acts and carelessness. The findings of RCCI teams therefore also serve a preventive purpose: they enable more targeted checks, guidance for municipalities and protective requirements, for example for outdoor work, cigarette handling or the maintenance of fire-prone areas.