Master jeweler Stephen Portier said the Louvre robbers might recut the stolen gems, which would significantly decrease their value.

Thieves used a stolen truck-mounted moving lift to scale the Louvre and steal royal jewels worth over $100 million in a lightning-fast Paris heist.

The only camera monitoring the exterior wall of the Louvre where they broke in was pointing away from the first-floor balcony that led to Gallery of Apollo housing the jewels, she said. "We failed these jewels," she said, adding that no-one was protected from "brutal criminals - not even the Louvre".

Officials say an outdated surveillance system left the world-famous museum in Paris vulnerable despite years of warnings.

Thieves snatched jewelry valued at more than $100 million, but the museum will not be compensated for the loss.

French investigators continued to search for eight stolen items after unidentified thieves carried out a daring daytime heist at the Louvre.

The Louvre in Paris reopened on Wednesday, three days after thieves made off with historic jewellery worth an estimated 88 million euros ($102 million) in a spectacular heist that has raised urgent questions over security lapses at the museum.