Thieves have ripped a safe from the wall of a hotel room near the Cannes Film Festival and made off with around $1m (€780,000) worth of jewellery.
The late-night burglary happened just hours after the screening of Sofia Coppola's Bling Ring, a film about break-ins at the homes of Hollywood celebrities.
The well-planned robbery at the Novotel hotel took place in the room of a representative of Chopard, the Swiss-based watch and jewellery maker and festival sponsor that was hosting a gala event in a far ritzier hotel around the same time, officials said.
The jewellery was "very probably" in the Novotel in connection with the festival, said Cmdr Bernard Mascarelli, a judicial police spokesman in nearby Nice, though he didn't know who it might have been intended for.
Chopard has loaned jewellery to A-list stars who walk on the festival's famed red carpet under rapid-fire flashes of photographers' cameras.
Already this year model Carla Delevingne and actress Julianne Moore have walked the carpet in Chopard gems.
Mr Mascarelli said he didn't know the exact type of jewellery taken or their exact value. "Numbers have been put forward that we're still trying to verify, but the figure of $1 million... we're in that range," he said.
Jean-Michel Caillau, a state prosecutor in nearby Grasse, who is leading an investigation, said early estimates were that the loot could have been worth as much as $1.4m. He also said the theft appeared to have taken place around 2.30am yesterday – around the same time as Chopard's gala was running late at the 5-star Hotel Martinez across town.
Chopard declined immediate comment, as did Melissa Levine, a spokeswoman for Accor, the French hospitality giant behind Novotel.
Dozens of police were involved in the investigation, and police vehicles could be seen outside the hotel yesterday afternoon. Authorities were going over hotel surveillance cameras and questioning potential witnesses who might have seen any culprits.
"It seems pretty unlikely to us that it was just one person," Mr Mascarelli said.
"Apparently this (hotel guest) was someone who was targeted because it wasn't someone who had been seeking attention. There must have been either an inside complicity, or people who were in contact with this person and knew that the person had jewels," he said.
On Thursday night, Chopard hosted a star-studded gala, and the festival screened Sofia Coppola's The Bling Ring – a deadpan drama about celebrity-obsessed teenagers in Los Angeles who break into the homes of Paris Hilton and other stars.
News of yesterday's robbery sent journalists scurrying to the Novotel, a business hotel about a 15-minute walk from Cannes' seafront promenade.
Chopard has a suite at the Martinez during the festival. The company also manufactures the crystal and gold Palme d'Or trophy awarded each year to the festival's top film. It was said to be safe.