The intruders are believed to have used an angle grinder and a blowtorch to gain access to the famous museum in the French capital. The police suspect that the thieves took advantage of the fact that the building's alarm system had been shut down after a hacker attack during the summer.
The thieves got away with gold worth 600,000 euros, 6.6 million kronor, in the form of so-called solid gold - gold particles found in other minerals.
Several other notable break-ins and thefts have occurred at French museums recently. A few weeks ago, valuable Chinese porcelain was stolen from a museum in Limoges and in November, several valuable 18th-century paintings were stolen from a museum in Paris. The day after, an armed robbery was carried out at a museum in Saone-et-Loire where the perpetrators got away with jewelry worth several million euros.