A Chinese woman has been arrested and charged over the theft of gold from the Natural History Museum in Paris, in one of several recent high-profile break-ins targeting French cultural institutions, a prosecutor said Tuesday.

The theft — by what the museum’s director at the time said was an “extremely professional team”- took place on September 16, a little over a month before an audacious jewellery heist at the world-famous Louvre museum on Sunday.

A 24-year-old Chinese woman was arrested in Barcelona on September 30 over the Natural History Museum break-in and theft of gold worth more than $1 million, Paris prosecutor Laure Beccuau said.

The suspect was handed over to French authorities on October 13 and was charged with theft and criminal conspiracy and put in provisional detention the same day.

Investigations showed she had left France the day of the break-in and was preparing to return to China. At the time of her arrest, she was trying to dispose of nearly one kilogram (2.2 pounds) of melted gold pieces, the prosecutor said, without providing more details.

The Natural History Museum curator discovered the theft of exhibited gold nuggets after a cleaner reported debris on site. The stolen items included nuggets from Bolivia donated in the 18th century, from Russia’s Ural region gifted by Tsar Nicholas I in 1833, and from California dating to the gold rush era.

A five-kilogramme nugget from Australia discovered in 1990 was also taken, Beccuau said. Nearly six kilograms of native gold was stolen, with damages estimated at 1.5 million euros ($1.7 million), she added, noting that the historical and scientific value of the pieces was “priceless”.

Native gold is a metal alloy containing gold and silver in their natural, unrefined form.

Investigators found two museum doors had been cut with a grinder and the display case breached using a blowtorch. Tools including a blowtorch, grinder, screwdriver, gas cylinders and saws were recovered nearby.

Surveillance footage showed a lone intruder entering the museum shortly after 1:00 am and leaving around 4:00 am, according to Beccuau. The investigation is ongoing, she added.

Police are also still on the hunt for thieves who stole priceless royal jewels from the Louvre museum in a spectacular daylight robbery on Sunday. The heist has reignited a row over a lack of security in France’s museums.