French authorities have launched a major manhunt after a gang of masked thieves staged a brazen daylight robbery at the Louvre Museum on Sunday, making off with royal jewels described by officials as “priceless.”

According to Interior Minister Laurent Nuñez, the suspects carried out the theft “within minutes” of the museum’s opening. Using a mechanical ladder, the group accessed a first-floor window of the Gallery of Apollo, smashed display cases, and escaped on mopeds before police could respond.

Investigators say the thieves targeted the Gallery of Apollo, home to France’s royal jewels, including pieces that once belonged to Empress Eugénie, wife of Napoleon III.

Among the nine stolen items were a brooch and a pair of emerald earrings from the 19th century. The Empress’s elaborate diamond and emerald crown, featuring golden eagles and encrusted with 1,354 diamonds and 56 emeralds, was recovered nearby — apparently dropped as the robbers fled in haste.

“The operation was over in less than five minutes,” a police official told Le Monde. “They knew exactly what they were looking for.”

Paris prosecutors said the gang used battery-powered disc cutters to break through security barriers. Two of the four suspects reportedly entered the museum and threatened guards, while their accomplices waited outside.

A vehicle-mounted extendable ladder, believed to have been used in the break-in, was discovered abandoned near the River Seine. Authorities said the thieves attempted to set the vehicle on fire, but a quick-thinking museum employee managed to extinguish the flames before the blaze spread.

No injuries were reported.

Interior Minister Nuñez described the theft as an attack on “France’s national heritage,” calling the jewels “of immeasurable cultural value.”

“Their significance to our history far exceeds their monetary worth,” he said, adding that police are working with Interpol and European law enforcement agencies to track the suspects.

Experts fear the jewels may be dismantled and sold for their gemstones, which are more difficult to trace than entire artifacts or paintings.

The Louvre Museum was evacuated and closed for the day as police combed the building and surrounding areas for evidence. Tourists arriving at the site were turned away, many unaware that a major heist had just taken place.

“We were just walking through the galleries when security told everyone to leave,” said Jim Carpenter, an American tourist visiting from Chicago. “At first, we thought it was a drill — then we saw police running in.”

The Louvre, the world’s most visited museum, has faced several high-profile security incidents in recent years, but officials say this theft — bold, fast, and meticulously executed — is the most serious in more than two decades.

As investigators review surveillance footage and forensic evidence, Paris remains on alert — and the hunt for the “Louvre jewel thieves” continues.