A live TV interview with stars Christoph Waltz and Daniel Auteuil was curtailed after shots were heard.
The two shots came from a starting pistol and sent the assembled actors, crew and audience scrambling for cover. They came during a live interview by French TV station Canal+ on a beach front set.
The interview was with 'Django Unchained' star Christoph Waltz and Daniel Auteuil ('Caché') for the station's show 'Le Grand Journal' near the Martinez Hotel on the eastern end of the roughly mile-long spur of Cannes' Boulevard de Croisette.
[$1 million of jewels stolen at Cannes]
Police arrived within minutes of the incident and a man was taken away. It was later confirmed that he was also carrying a dummy grenade and a knife. However, host Michel Denisot said the shots had been blanks and that there were no injuries.
The show resumed a few minutes later with the producer saying "the show must go on."
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The incident follows earlier news that more than $1m worth of Chopard jewellery was stolen from Novotel Suites in Cannes ahead of the film's red carpet ceremony on Friday morning.