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