Robber Steals $53M in Jewels at Cannes Hotel The gunman walked into the luxury Carlton hotel in broad daylight.

July 28, 2013 -- The Cannes, France, hotel that served as the setting for one of the most famous jewel heist movies of all time today was the scene of a brazen armed robbery, when a gunman made off with an estimated $53 million in jewels and diamonds from a gem exhibition.

It was the third such heist in the French Riviera resort in as many months.

The gunman walked into the luxury Carlton Intercontinental Hotel at around noon and headed for "La Cote," a room housing a temporary exhibit of jewelry by the prestigious Leviev diamond house, owned by the London-based Russian Israeli billionaire Lev Leviev, that had been due to run until the end of August.

"The thief in his mid-40s entered the room of the exhibition, pulled a Colt .45 out at the employees, stuffed a bag with gems and walked out of the hotel," a Cannes police officer, speaking on condition of anonymity, told ABC News. "We do not know yet if the thief had accomplices, but we are investigating everything. It's a full scale investigation."

The robbery was "very quick," Philippe Vique, deputy prosecutor for Grasse, said.

"The thief, wearing a cap and a scarf around his neck, threatened employees and armless security with a gun," Vique said. "There was no violence. He grabbed jewelry with diamonds and put them in a bag and walked away."

Though the thief came in alone, police are investigating to see whether he had accomplices, the prosecutor said.

"We are looking into CCTV footage from hotel, but also from the city," he said.

The Carlton hotel dominates the exclusive Promenade de la Croisette that stretches a mile and a half along the French Riviera.

It was a movie set hotel for "To Catch a Thief," the 1955 Alfred Hitchcock romantic thriller starring Cary Grant as a former jewel thief and Grace Kelly as an American heiress on holiday in the Riviera with her mother.

The Carlton hotel is also where Kelly met her future husband, Prince Rainier of Monaco, for the first time -- at the prince's request -- during the Cannes Film Festival.

Cannes is a popular target for a group of international jewel thieves known as the Pink Panthers, after the popular comedy crime films starring Peter Sellers as the bumbling Inspector Clouseau.

Vique said that at this stage, they have not found a link to that group.

"At the moment I have nothing to think it's Pink Panthers, but we are not excluding anything," he said. "We will investigate everything, but this is still an early stage."

The Carlton itself was already a scene of one of the biggest diamond robberies, in August 1994, when a group of thieves firing machineguns burst into the hotel's jewelry store and made off with some $60 million in diamonds.

The latest robbery comes just over two months after a safe containing more than $1 million of jewelry designed by the exclusive Swiss-based jeweler and watchmaker Chopard was taken from a Novotel hotel room during the city's film festival in May.