A volunteer firefighter who was suspected of starting a fire in France's historic Fontainebleau forest was placed under formal investigation and remanded in custody on Wednesday, a prosecutor said.

By Monday afternoon the fire had raced across almost 1,000 hectares, forcing some residents from their homes in the normally quiet forest.

A total of 59 people have been arrested across France over suspected deliberate or accidental arson, including two in connection with the wildfire still sweeping through the…