Security protocols failed in preventing a major jewellery heist at the Louvre museum in Paris, leaving the country with a terrible image, France's justice minister has said.
Thieves wielding power tools broke into the world's most-visited museum in broad daylight on Sunday, stealing eight items described as of inestimable value, before escaping on scooters.
Security measures have been tightened around France's cultural institutions, advisers for the country's interior minister said.
There are fears that, unless the thieves are caught quickly, the priceless items, including a diamond and emerald necklace Emperor Napoleon gave to his wife, will be broken down and smuggled out of the country.
The Louvre announced it would remain closed on Monday while investigations continued.
French media reports that a preliminary assessment by the Court of Auditors (due to be published in November) found that a third of the rooms in the wing where the robbery took place have no surveillance cameras.
What is certain is that we have failed, since people were able to park a furniture hoist in the middle of Paris, get people up it in several minutes to grab priceless jewels, Justice Minister Gérald Darmanin told France Inter radio.
He added that he was certain police would eventually arrest the thieves.
The head of an organisation specialising in the location and recovery of stolen artworks warned that if the thieves were not caught in the next 24-48 hours, the stolen jewellery would likely be long gone.
The theft took place between 09:30 and 09:40 local time on Sunday morning, shortly after the museum opened to visitors.
Four masked thieves used a truck equipped with a mechanical lift to gain access to the Galerie d'Apollon (Gallery of Apollo) via a balcony close to the River Seine.
The thieves smashed the glass display cases and stole jewels that collectively contain thousands of diamonds and precious gemstones. The entire robbery was over in around eight minutes.
As the museum's alarms started blaring, staff followed protocol by contacting security forces, the culture ministry said in a statement.
Eight items of jewellery were stolen in total, including an emerald and diamond necklace that Napoleon gifted his wife, Empress Marie Louise.
Also taken was a diadem (jewelled headband) that once belonged to the Empress Eugénie - Napoleon III's wife - which has nearly 2,000 diamonds.
French President Emmanuel Macron described the robbery as an attack on a heritage that we cherish because it is our history.
Interior Minister Laurent Nuñez acknowledged a great vulnerability in museum security in France.
There is a race against time for the jewels, as experts warn that their breakdown and sale in small parts is a likely outcome unless quick action is taken.