The royals are seeking an injunction and damages from the French gossip magazine Closer that first published the candid shots last week.
The couple will also lodge a criminal complaint with French prosecutors seeking charges against the photographer who snapped the topless photos and the French magazine Closer that printed them.
However the legal action comes the same day as Italian magazine Chi plans to devote a special issue to the paparazzi photographs of the Duchess of Cambridge taken suring a royal holiday in France this month.
"We can confirm that a criminal complaint is to be made to the French Prosecution Department tomorrow (Monday)," a St. James's Palace spokeswoman said late Sunday.
She said it would be up to French prosecutors to decide whether to investigate and pursue the complaint.
In court Monday lawyers for the Duke and Duchess of Cambridge will seek an injunction at a hearing in the Paris suburb Nanterre to prevent the magazine Closer from re-selling the pictures of Catherine's semi-naked sunbathing, which they argue breached her privacy.
They hope in the longer term to win damages from Closer, part of Italian ex-prime minister Silvio Berlusconi's media empire, for publishing the photos taken with a telephoto lens as the couple holidayed in southern France.
They will also seek to block Closer from printing more copies of the edition that appeared Friday with the story on the front page and spread across five pages inside under the headline: "Sex And Sun En Provence".
The prince is furious over the images, which drew comparisons with press harassment of his mother Diana who died in a Paris car crash in 1997 while pursued by paparazzi.
No newspaper or magazine in Britain – whose racy, mass-selling tabloids have frequently been accused of unwarranted intrusion into the lives of the rich and famous – has announced plans to publish the offending photographs.
But the threat of legal action failed to intimidate Irish or Italian titles, with the pics of Catherine sunning herself in bikini briefs appearing Saturday in a Dublin tabloid and Chi magazine promising to publish and be damned.
"There can be no motivation for this action other than greed," said a spokeswoman for Catherine and her husband, the second-in-line to the British throne.
Both Closer and Chi are published by Berlusconi's Mondadori Group, which has backed both magazines' decisions to print the photos of the pair as they relaxed at a private chateau.
"The editors of both titles decided to publish the photos because their content is a clear expression of the news, they depict a true event, and they do not undermine the people photographed," Mondadori said in a statement.
Chi magazine's editor Alfonso Signorini said the pictures were "a scoop" he could not afford to miss.
"If I wasn't capable of recognising the true value of a scoop I would do better to go and sell artichokes at the market," he told the ANSA news agency, adding that he did not ask Berlusconi's permission to print the images.
A palace spokeswoman declined to comment on whether the royal family was launching legal action against either Chi or the Irish Daily Star.
"All proportionate responses will be kept under review," she said.
Unlike Mondadori, the two media groups that jointly own the Irish Daily Star condemned its decision to run the pictures.
Britain's Northern and Shell group said it was taking "immediate steps" to shut down the joint venture with Dublin-based publisher Independent News and Media which runs the Irish Daily Star.
The tabloid's editor Mike O'Kane admitted that he was running the pictures to sell more papers, and said he had treated Catherine as he would any other celebrity.
"She's not the future queen of Ireland so really the only place this is causing fury seems to be in the UK," he told the BBC.
The palace has said the couple "remain focused" on their nine-day southeast Asian and Pacific tour marking Queen Elizabeth's 60 years on the throne, which on Sunday took the couple, who are both 30, to the lush Solomon Islands.