Many were given only minutes to leave as hundreds of firefighters were deployed in the Var region to the west of Saint-Tropez.
Fire officials say the blaze broke out on Monday and has consumed some 6,000 hectares (14,820 acres).
Twenty people suffered smoke inhalation and six firefighters were hurt.
BBC TV presenter Geeta Guru-Murthy described fleeing on foot as flames approached on both sides of the road.
