Hundreds of people were ordered out of their homes in eastern Marseille as a precaution and a rest home and centre for the handicapped was evacuated.
Jean-Claude Gaudin, Marseille's mayor, said the shooting was a case of "incredible stupidity" at a time when scrub lands were vulnerable to fires.
Normally shooting tracer bullets is forbidden from May to November in the region because of fire risk.
French police visited the site on Thursday to re-enact the shooting.
A few new blazes ignited on Thursday, as helicopters circled and about 500 firefighters were mobilised in the area.