On the final day of the historic festival, the 49-year-old actor - who is best known for starring in the Taxi film series - was approached by a group of autograph seekers as he walked along the Promenade de la Croisette.
According to French newspaper Nice Matin, Naceri declined the fans' request for his signature and then exposed his backside.
He was later taken into custody by the local authorities on suspicion of public exposure.
Naceri has had numerous legal problems in recent years, having served jail time for separate substance abuse and assault charges.
The Cannes Film Festival had previously been the site of one the star's great professional triumphs when he won the 2006 'Best Actor' prize for his performance in Days of Glory.
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