The robbery is likely to raise awkward questions about security at the museum, where officials had already sounded the alarm about lack of investment at a world-famous site that welcomed 8.7 million visitors in 2024. The thieves struck at about 9.30 a.m. (0730 GMT) when the museum had already opened its doors to the public, and entered the Galerie d'Apollon building, the Interior Ministry said in a statement. The robbery took around four minutes, Culture Minister Rachida Dati told TF1, and it was carried out by professionals. "We saw some footage: they don't target people, they enter calmly in four minutes, smash display cases, take their loot, and leave. No violence, very professional," she said on TF1. She said one piece of jewellery had been recovered outside the museum, apparently dropped as they made their escape. Dati declined to say what the item was, but newspaper Le Parisien said it was believed to be the crown of Napoleon III's wife, Empress Eugénie. The jewel was broken, the newspaper said. Interior Minister Laurent Nuñez told France Inter that three or four thieves got into the museum from outside using a crane that was positioned on a truck. "They broke a window, headed to several display cases and stole jewels ... which have a real historical, priceless value," Nuñez said. Probe underway A video posted on X by a museum guide showed visitors filing towards exits in the middle of their tour, initially unaware of the reason for the disruption. Nuñez said a probe had been opened, with a specialized police unit that has a high success rate in cracking high-profile robberies such as this one tasked with running it. No injuries were reported, Dati said. The Louvre, the world's most-visited museum and home to Leonardo da Vinci's Mona Lisa, said on X it would remain closed for the day for "exceptional reasons".