The train, operating between Rouen and Caen in Normandy, derailed shortly before 20:00 local time (18:00 GMT) on Friday. According to Transport Minister Philippe Tabarot, 180 passengers were on board. An 18-year-old woman was airlifted to hospital in critical condition.
Local authorities activated a mass-casualty response plan, deploying around 140 firefighters and other emergency teams to the scene. Al Jazeera reported that 130 firefighters and five medical teams were dispatched; the discrepancy in the firefighter count could not immediately be reconciled. French media reported that three carriages overturned. Photographs showed passengers evacuating the train.
The cause of the derailment was not immediately known. France's state-owned railway operator SNCF reported "significant disruptions" on its routes in the area and said replacement buses would be provided. Authorities advised the public to avoid the area.