PARIS (Reuters) - Police are hunting across France for seventeen rare monkeys stolen from a zoo south of Paris over the weekend, the zoo's director said on Tuesday.

The seven golden lion tamarins and 10 silver marmosets, all owned by the Brazilian government, were taken on Saturday from the Beauval zoo, about 200 km (120 miles) from Paris, by what officials said were "experts".

"No idea why they were taken. It's an outrageous theft. These are extremely fragile animals that need specific care," zoo director Rodolphe Debord told Reuters.

Despite security cameras and extra night patrols, the thieves were able to cut through a glass window to steal the monkeys. Police had opened an investigation and were trawling through CCTV footage, he said.

"These are extremely rare, threatened monkeys," Debord said, noting it was a big loss for the conservation of the species.

The monkeys had specific dietary requirements and vets had been treating one of them daily for an injury to its tail.

"These thieves knew exactly what monkeys they wanted to steal," he said. "There are two possibilities. Either a collector or the black market for new types of pets," he said.

France-based environmental association Robin des Bois said in a statement that there had been a rise across the world in the smuggling of rare monkeys since 2011, including the theft of five tamarin monkeys in Blackpool in April 2014.

A tamarin can fetch between 5,000 euros ($5,600) to 10,000 euros on the black market, it said.

(Reporting by Mourad Guichard and John Irish; Editing by Louise Ireland)