Cultural institutions are seen as “soft targets,” experts say, as thieves shift from stealing prized paintings, to artifacts that can be dismantled, stripped or melted down for their expensive parts.

Thieves broke into the museum's Galerie d'Apollon and made off with "priceless" jewelry, French interior minister Laurent Nuñez said.

The Lourvre museum was hit by a brazen daytime jewel heist, forcing the Paris institution to close its doors for a second day in a row.

The Louvre museum in Paris announced it would remain closed Monday as investigations continue into Sunday’s extraordinary theft of historic jewelry – and experts say the prospects of recovering the treasures are slim.

Authorities were racing Monday to reassure the public about security at key cultural sites — and find the jewels stolen from the museum before they can be broken up and melted down.

Paris Prosecutor Laure Beccuau says thieves who stole priceless jewelry from the Louvre Museum in a seven-minute heist may have been hired by a collector.

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.