Brandishing a semi-automatic pistol, his head covered with a cloth, the robber stole jewels that were part of an exhibition by a group owned by Israeli billionaire Lev Leviev.
French authorities said he escaped with all kinds of jewellery, including rings, pendants, and diamond-encrusted earrings, worth an estimated 103 million euros.
Cannes has fallen prey to other jewel thefts several times recently, and during this year's film festival in May.
At the festival, which attracts a glittering array of celebrities, thieves stole jewellery worth $1.4 million due to be loaned to movie stars.
Yet another theft during the festival saw robbers make off with a diamond necklace with an estimated value of $1.9 million.
At least two apartments rented by film executives were also burgled during the 2013 festival, with thieves taking cash, jewellery and other personal items.
- AFP