Its flames spread rapidly from a wooded area towards the sea, eight kilometers (five miles), sweeping through residential areas and several campgrounds. Firefighters rushed to evacuate the campers by land and sea.
The cause of the fires is not known.
Eight civilians and 14 firefighters were lightly injured in the Martigues blaze and five others that broke out in the region on Tuesday, firefighters said. The other fires were brought under control in the towns of Port-de-Bouc, Aubagne-Carnoux, Gignac-la-Nerthe and Fontvieille.
Given the lingering winds Wednesday morning and dry, hot weather across France, authorities have banned any controlled fires in the area or construction work involving sparks or hot equipment until the fires are extinguished.
Interior Minister Gérard Darmanin rushed to the site overnight and fire teams were dispatched from other areas to help.