Lawyers for the Duke and Duchess of Cambridge have begun a bid in a French court to stop the sale and distribution of topless pictures of the duchess.
Their lawyer called for French magazine Closer to hand over the digital originals or face a large daily fine, during a hearing in Nanterre, Paris.
A lawyer for Closer claimed the couple's reaction was disproportionate.
Aurelien Hamel, the French lawyer representing Prince William and Catherine, was first to speak when the civil action began, shortly after 17:00 BST.
Mr Hamel told the court that the scenes captured were intimate and personal, with no place on the front page of a magazine.
He said the couple could not have known they were being photographed, adding it would only have been possible to see them with a long lens.
He said that if the original digital images were not handed, the company that owns Closer should face a fine of 10,000 euros (ÂĢ8,000) for each day of non-compliance.
In response, Delphine Pando, representing Closer, said that topless photographs in general were no longer considered shocking in modern society.
Under French law, the damages related to legal proceedings could run into tens of thousands of euros and, in theory, the magazine editor and photographer could be sent to jail for a year.
She has already defended publication, insisting the photos were not the least bit shocking, and has suggested that she has more intimate photos not yet published.
A palace spokeswoman said: "We can confirm that a criminal complaint is to be made to the French Prosecution Department.
"It concerns the taking of photographs of the Duke and Duchess of Cambridge whilst on holiday and the publication of those photographs in breach of their privacy."
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