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 daily fine, during a civil hearing in Nanterre near Paris.
A lawyer for Closer claimed the couple's reaction was disproportionate.
Meanwhile Irish Daily Star editor Michael O'Kane has been suspended over its publication of the photographs.
The Dublin-based paper's co-owners, Independent News and Media, confirmed that he was suspended while an internal investigation takes place.
The three magistrates presiding over the civil case in Nanterre are expected to announce whether an injunction will be granted at 11:00 BST on Tuesday.
After first appearing in Closer last week, the pictures were used on foreign websites, in the Irish Daily Star and most recently, in Italian gossip magazine Chi.
At the court Aurelien Hamelle, the lawyer representing Prince William and Catherine, was first to speak when the civil action began, shortly after 17:00 BST.
Mr Hamelle said the scenes captured were intimate and personal and had 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 over, the company that owns Closer should face a fine of 10,000 euros (£8,000) for each day of non-compliance.
In response, Delphine Pando, representing Closer, said that topless photographs were no longer considered shocking in modern society.
She added that the couple's reaction had drawn further interest from the press.
Ms Pando denied that the chateau where the couple were sunbathing was inaccessible to public view. She also said the magazine did not hold the rights to the pictures, so it could not be proved that the magazine intended to republish them.
The BBC's Paris correspondent Christian Fraser said there was no name listed in the criminal complaint because the royals do not know the name of the photographer.
He said most lawyers seemed to agree that under strict French law the pictures represented an undisputed breach of privacy - an open-and-shut case.
The action did not stop Closer's Italian sister magazine, Chi, from publishing the same photos but the speed with which the royal couple have acted may deter others from publishing the pictures.
Chi printed a special edition featuring more than 20 pages of the photographs.
It carries a picture of the duchess, topless, on its front cover with a headline that reads: "The Queen is Nude!"
In an editorial the magazine's director, Alfonso Signorini, attempted to justify the decision to print the images by saying he considered them to be "normal and up to date with the times".
He said: "Why, I wonder, Kate Middleton, for now Duchess of Cambridge but future queen of the United Kingdom, should be different from girls her age?
"In the end, the royals are people like any other. Of course they have obligations, duties - but also privileges."
Mr Signorini said the series of pictures were "not particularly sensationalistic nor damaging to her dignity" and "surely makes her more likeable" and "less distant from all of us".
Closer and Chi are both part of former Italian prime minister Silvio Berlusconi's Mondadori media group.
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.
Closer editor Laurence Pieau has already defended publication, insisting the photos were not in the least bit shocking, and has suggested that she has more intimate photos not yet published.
Before the announcement of an investigation at the Irish Daily Star into its use of the pictures, the paper's co-owners - Britain's Northern and Shell group and the Dublin-based publisher Independent News and Media - had condemned the decision, saying they had no prior knowledge of it.
Richard Desmond, chairman of Northern and Shell, said he intended to withdraw from the Republic of Ireland, and had begun steps to close down the joint venture.
A source at the Irish Daily Star said the belief there was that Northern and Shell would pull out of the publication on Tuesday, when a board meeting of the paper is scheduled to take place.
Independent News and Media has described plans to close the publication as "disproportionate", while acknowledging that the paper had made a "poor editorial decision".
No British newspaper has printed the pictures, with the Daily Mail saying it had been offered similar pictures last week but had rejected them and the Sun saying that no responsible newspaper "would touch them with a bargepole".
Solomon Islands visit
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."
The photographs were taken while the duchess was sunbathing on a private holiday with her husband at the French chateau of the Queen's nephew, Lord Linley, in Provence.
Meanwhile, the royal couple have been in the Solomon Islands representing the Queen on their nine-day Diamond Jubilee tour of South East Asia and the South Pacific.
On Monday, they travelled to Marau, about 60 miles from Honiara, where they watched a warrior dance before going to the nearby island of Marapa.
After watching local women perform a shark dance in the water, the couple were taken in a traditional war canoe to the remote island resort of Tavanipupu, where they will spend the night before continuing on to Tuvalu, the last destination on their tour.