Thieves have stolen two diamonds worth about $14.1 million from a trade fair at one of Paris’ top museums.

The gems were taken from a display case at an antique and jewelry dealers show at the Louvre Museum complex. The thieves pounced when employees left the Chopard booth for about 15 minutes, the BBC reports. The the theft happened in broad daylight in one of the most public places in the city, and that there was no violence.

It appears that the display case was not alarmed, although there are many security cameras in the complex, the BBC reports.

Police told the BCC the apparent lack of security is “rare.”

The biggest diamond stolen was a 47-ct. jewel worth an estimated $7.4 million. The other stone taken was about 30 cts. and worth about $6.7 million.

Security measures for the exhibition were not connected to the security for the Louvre Museum itself, which houses some of the world’s priceless works of art, such as Leonardo da Vinci’s Mona Lisa.

The Antique Dealers Biennale at the Carrousel du Louvre, which runs Sept. 15-28, brings together more than 100 antiques and jewelry dealers.

Also on display at the Biennale was the 128.48-ct. “Star of the South” – one of the world’s most famous diamonds known for its pinkish-brown color.

Cartier had put the precious gem up for sale.

JCK