Publication or resale of topless pictures of Prince William's wife Catherine in Closer magazine is banned by the French authorities on Tuesday and also launched a criminal investigation.
An emergency injunction granted by a civil court at Nanterre in the Paris suburbs ordered the magazine to hand over all forms of the pictures to representatives of the British royal couple within 24 hours or face a 10,000-euro ($13,000) fine for every day's delay.
The injunction also bans the glossy magazine, which published the pictures on Friday, from reusing them in print or on its website and from re-selling them. Each infraction will be subject to a 10,000-euro fine.
Versions of the grainy pictures are already widely available on the Internet and have been printed in Ireland's Daily Star newspaper and Italy's Chi magazine.
The granting of the injunction came hours after a prosecutor launched a preliminary investigation into whether the magazine and the photographer or photographers who took the pictures had committed a criminal act.
The move followed a complaint lodged by the royal couple on Monday.
In light of the granting of the injunction, it is virtually certain to lead to a full investigation of allegations that taking and publishing the pictures breached the couple's right to privacy under French law.
The injunction ruling said the pictures were "by their nature, particularly intrusive" and had been taken in a place where the couple could "legitimately assume they were not overlooked."
The prosecutor will have to decide who any criminal proceedings are directed against.
The royals' complaint cites persons unknown but aides say they want proceedings against both the editor of Closer and the photographer (or photographers) who took the shots of the couple at a chateau in the south of France earlier this month.
In theory both could face fines of up to 45,000 euros and possibly even prison terms if convicted. In practice, no-one has ever been imprisoned for breaching the privacy law and fines are usually well below the maximum allowed.
The couple's lawyer Aurelien Hamelle had told the injunction hearing that the images of William and his wife were of "a highly intimate moment" in the life of a young married couple that had no place on the cover of a magazine.
The lawyer also argued that the images were particularly distressing for the couple in light of William's mother Princess Diana's 1997 death in a car that crashed in a Paris tunnel while being pursued by paparazzi.
The pictures were taken while the couple sunned themselves on the terrace of the chateau.
The most intimate shots show the former Kate Middleton topless and having suncream rubbed into her behind by William.
The identity of the photographer who took the snaps remains unknown and French law protecting journalistic sources mean Closer is unlikely to be forced to name him or her.
Chi editor Alfonso Signorini has argued that the pictures had legitimate news value because they showed a different face of the British monarchy and that no law was broken because they were taken from a public road, a defence that will also be used by Closer in the event of a criminal trial.
Both the French edition of Closer and Chi magazine are owned by former Italian premier Silvio Berlusconi's Mondadori group.
Unlike Mondadori, the media groups that jointly own the Irish Daily Star have condemned its decision to run the pictures.
Editor Michael O'Kane has been suspended and the paper's future is in doubt following the announcement by its British joint-owner Northern and Shell that it would be withdrawing from its partnership with Ireland-based Independent News and Media.