It didn’t take long for Prince William and his wife to strike back at a French magazine that’s published five pages of photos of Catherine sunbathing topless.

The royals announced a lawsuit within hours of the magazine’s release Friday, alleging the publication breached their right to privacy.

Earlier, the Royal Family said it was furious with the photos and called them a "grotesque and totally unjustifiable" invasion of privacy.

"The incident is reminiscent of the worst excesses of the press and paparazzi during the life of Diana, Princess of Wales, and all the more upsetting to the Duke and Duchess for being so," St. James's Palace said in a statement.

“Their Royal Highnesses had every expectation of privacy in the remote house. It is unthinkable that anyone should take such photographs, let alone publish them.”

The editor of Closer said his magazine saw no harm in releasing the shots.

“These photos are not in the least shocking. They show a young woman sunbathing topless, like the millions of women you see on beaches,” Laurence Pieau told AFP.

Closer says the photos were taken on a guesthouse terrace of the Autet Chateau in Provence, where the couple vacationed this month. The chateau is owned by Viscount Linley, the son of the Queen's late sister, Princess Margaret.

The grainy shots appear to have been taken from a distance using a high-powered lens.

They show the Duchess wearing a black and white bikini, then removing her bikini top to relax on a lounger, apparently oblivious to the nearby cameras.

The headline on the French-language magazine reads: "Oh my God!"

One of the photo captions reads: “The last time we saw Kate and William on a balcony it was for their wedding. But they had more clothes on.” Another says: "People always say she doesn't need to dress up to look good. Well... Kate is proving this."

The captions also note the Duchess is so toned that "Victoria's Secret angels can stand aside."

Closer also said Kate was spotted smoking a cigarette as the couple walked out of nearby Marseille airport.

The photos come as the Royal Family tries to move past a photo scandal involving Prince Harry, who was caught on camera cavorting naked with young women during a trip to Las Vegas.

William and Kate are currently in Malaysia as part of a tour of the Far East and South Pacific to mark the Queen's Diamond Jubilee.

Meanwhile, British publications are avoiding re-publishing the shots. The Sun, which last month was the sole British newspaper to publish the Prince Harry snaps, says that situation was different because publication was in the public interest.

The Sun’s editor, Dominic Mahon, said his newspaper would not be printing the Kate photographs.

"The Sun has no intention of breaching the royal couple's privacy," he told AFP.

Closer France is published by Mondadori, an Italian company owned by former Italian prime minister Silvio Berlusconi.