French Justice Minister Gerard Darmanin said on Monday the jewelry heist at the Louvre museum on Sunday gave a very negative image of France as it implied a failure of security services.
"There are many museums in Paris, many museums in France, with priceless values in these museums," Darmanin said in an interview with French radio station France Inter.
"What is certain is that we failed," he said, adding the police will eventually arrest the thieves.
Officials said a team of 60 investigators were working on the theory that the raid was planned and executed by an organized crime group.
The thieves arrived between 9:30 and 9:40 am (0730 and 0740 GMT) Sunday, shortly after the museum opened to the public at 9:00 am, a source close to the investigation said.
They used a furniture hoist to get access to the Apollo Gallery, home to the royal collection, and cutting equipment to get in through a window and open the display cases.
A brief clip of the raid, apparently filmed on the phone of a visitor to the museum, was broadcast on French news channels.
The masked thieves stole nine 19th-century items of jewelry, one of which -- the crown of the Empress Eugenie -- was dropped and damaged as they made their escape.
Eight "priceless" items of jewelry were stolen, the culture ministry said Sunday. The list they released included an emerald-and-diamond necklace that Napoleon gave his wife Empress Marie Louise.
Also stolen was a diadem that once belonged to the Empress Eugenie, which has nearly 2,000 diamonds; and a necklace that once belonged to Marie-Amelie, the last queen of France. It has eight sapphires and 631 diamonds, according to the Louvre's website.
The whole raid took just seven minutes and was thought to have been carried out by an experienced team, possibly "foreigners,” said Interior Minister Laurent Nunez.
The intervention of the museum's staff forced the thieves to flee, leaving behind some of the equipment used in the raid, said the Culture Ministry in a statement.
