Paris Louvre museum. Photo courtesy of the museum official X account.
"A robbery took place this morning at the opening of the Louvre Museum," Dati wrote on X.
"No injuries reported. I'm on site with museum staff and police," she added.
At least one person had entered the museum, a member of her team told AFP, without adding anything about any possible theft.
The Louvre said it was closing for the day "for exceptional reasons".
Robbers broke into the Louvre and fled with jewellery, a source close to the case said, adding that its value was still being evaluated.
A police source said an unknown number of thieves arrived on a scooter armed with small chainsaws and used a goods lift to reach the room they were targeting.
The thieves arrived between 9:30 and 9:40 am (0730 and 0740 GMT) and stole jewellery, a source following the case said, adding its value was still being estimated.
France's Interior Minister Laurent Nunez said that jewellery stolen from the Louvre Museum in Paris was "priceless".
The minister told French news outlets France Inter, France Info, and Le Monde that "three or four" thieves had focused on two displays in the exhibition venue's "Gallerie d'Apollon" ("Apollo's Gallery"), completing their broad daylight robbery in just seven minutes.
The French authorities later, found a damaged 19th-century crown near the Louvre in Paris, a source following the case told AFP.
The crown once belonging to Empress Eugenie, the wife of Napoleon III, features golden eagles and is covered in 1,354 diamonds and 56 emeralds, according to the museum's website.
The seat of French kings until Louis XIV abandoned it for Versailles in the late 1600s, the Louvre is regularly listed as the world's most visited museum.
The exhibition venue welcomed nine million visitors last year.
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