Witnesses told police that an unidentified assailant opened fire near a metro station last night before fleeing, according to two Lille police officials.
The officials said one of those shot is a minor, and none of the injuries is life-threatening. The officials were not authorised to be publicly named.
The reason for the shooting is unclear. It comes as France is under a state of emergency after deadly extremist attacks.
Newspaper La Voix du Nord and radio France Bleu Nord reported that the Lille shooting may have been a settling of scores among local criminals.