A group of professional thieves stole jewels of “inestimable value” in a coordinated four-minute heist at the Louvre in Paris, French officials said on Sunday as the art museum shut down for the day.

Police were investigating the robbery and how it took place on Sunday morning. Preliminary details revealed the thieves used a mechanised lift to access upstairs windows for entry, per French newspaper Le Parisien. After breaking the windows, the culprits bagged nine Napoleonic jewels left on display and fled on scooters.