Prince William and Catherine, the duchess of Cambridge, will file a criminal complaint against the photographer who took topless pictures of her, the palace said Sunday evening.
The complaint will be given to a French prosecutor on Monday, Britain's Press Association reported.
Earlier, the palace said Britain's royal family will go to court Monday to stop the publication of more topless photos.
Lawyers for the royals will be seeking damages and a Paris court order preventing the photos from being published again. They also want existing photos taken offline, the palace spokesman told CNN.
The French magazine Closer ran photos last week of Catherine sunbathing topless in private.
Chi, an Italian gossip magazine owned by the same company, has said it will put out a special edition on Monday with photos of William and Catherine on vacation.
The royal couple is not pursuing legal action in other countries currently, the palace spokesman said, although the photos have also been published in Ireland.
The palace expressed outrage last week that the French magazine published the pictures, comparing the invasion of privacy to those suffered by William's late mother, Diana, princess of Wales.
William and Catherine were said to be "hugely saddened" by what palace officials called a "grotesque" invasion of privacy while they were on a private vacation.
But the Irish Daily Star went on to print the pictures on Saturday.
Palace officials slammed the newspaper's decision as driven only by greed.
But editor Mike O'Kane told the BBC that outrage over the images was only felt in Britain and that readers in the Republic of Ireland wanted to know what all the "kerfuffle" was about.
He was "a little taken aback by the reaction in the UK," he said, saying the newspaper was treating Catherine no differently from 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 said, suggesting that the British press were behaving with some hypocrisy.
O'Kane said the Irish Daily Star was reproducing the images as published in Closer on Friday rather than buying them directly. The pictures are not being published in the Northern Ireland edition.
Northern Ireland is part of the United Kingdom.
The latest controversy comes only three weeks after the British royal family was caught up in a media furor over images of William's younger brother, Prince Harry, partying naked in his Las Vegas hotel room with a group of girls.
In a sign of how divisive the issue of royal privacy has become, a co-owner of the Irish Daily Star, media group Northern & Shell, said it in no way backed the newspaper's decision to run the pictures of Catherine.
In a statement, the company -- which runs the Irish Daily Star in a joint venture with Independent News & Media, but does not exert editorial control over it -- said it was "profoundly dismayed" by the move.
"We abhor the decision of the Irish Daily Star to publish these intrusive pictures of the Duke and Duchess of Cambridge, which we, like St James's Palace, believe to be a grotesque invasion of their privacy," Northern & Shell's communications director Mimi Turner said.
Northern & Shell also owns the Daily Express and the Daily Star, among other British publications, which have not run the pictures of Catherine, nor of Prince Harry.
William, who is second in line to the throne, and his wife are on an official tour of southeast Asian nations.
They were due in the Solomon Islands Sunday on the next leg of a tour that has been overshadowed by the furor over the photographs.
Catherine was "upset" with Closer magazine, a palace source told CNN.
Mondadori told CNN it plans to run 26 pages of photographs of William and Kate on vacation in an "extraordinary" special edition to go on sale in Italy on Monday.