Moore said of the criminal contingent he fears will be flocking the Riviera this week: "It's a bit like spawning season. They are all drawn there. It's a bonanza for them."
He added: "You have stars and so on with jewellery worth millions, but when they are out at the afterparties, often their rooms are unguarded.
"They could be popping down to breakfast and someone can slip into their room.
"You've got fake cleaners and fake hotel staff, or people who have intentionally gotten employment there in order to pull off a burglary."
The 75th Cannes Film Festival opens on Tuesday and is set to welcome stars including Tom Cruise, Idris Elba and Lea Seydoux. It is understood security teams working to protect celebrity guests and national delegations will be wary of the town's reputation as a site of lucrative larcenies.
Last year tens of thousands of pounds worth of jewellery was taken from the suite of Turner-Smith at the five-star Marriott hotel on La Croisette, Cannes' most lavish boulevard, and the door to her room showed no signs of forced entry.
It became the fifth heist in Cannes in eight years and took place during a film festival made quieter than usual because of Covid-19 restrictions.
Moore believes the lifting of these restrictions will mean many more celebrities in the French resort town this year and more criminals seeking to target them.
He said: "You will have people looking to exploit the celebrities and the money heading to Cannes. With Covid, you have up-and-coming gangs who have been unable to operate looking to make a name for themselves and make some money."
Moore has said that even the climate can be a problem for security, with ubiquitous sunglasses in southern France providing an easy disguise, especially when combined with face masks
Cannes' "terrible" traffic is also likely to cause issues, with thieves on motorbikes able to pull up alongside the conspicuous luxury vehicles of celebrities, and rob them while they are stuck in traffic.
The talk of the festival this year is likely to be dominated by Cruise's Top Gun sequel, Baz Luhrmann's surreal film about Elvis Presley, and David Cronenberg's body horror Crimes of the Future.