"She's a real 21st century princess," she added: "It's a young woman who is topless, the same as you can see on any beach in France or around the world."
Pieau also claimed to have more "intimate" snaps of Wills and Kate.
"I won't hide the fact that there are more intimate pictures that exist that we haven't published and will not publish," she said.
Closer has since removed the controversial snaps from its website.
"Following comments received after the publication of photos of Kate and William in Closer magazine France, we would like to make the following clarifications: This is the French edition of Closer and not the English edition," the mag states in an online statement.
"The photos we chose are by no means degrading. They show a young couple on vacation, beautiful, in love, living a normal life. The article reports that the couple recently vacationed in the south of France."
26-PAGE SPREAD READY FOR PUBLICATION
An Italian magazine says it plans to publish the topless photos in a special 26-page issue this week, despite the threat of legal action.
Gossip magazine Chi has announced it plans to follow its French sister publication Closer in printing the topless shots of Prince William's wife Kate.
French scandal sheet Closer sparked controversy on Friday after it published paparazzi snaps of Kate while she privately sunbathed with her husband in Provence at a chateau owned by Queen Elizabeth II's nephew, Lord Linley.
The blurry photos show the duchess wearing a skimpy bikini bottom and sunglasses as she relaxed on a terrace with William.
In one of the snaps published on Closer's cover, she also appears to be rubbing suntan lotion on William's shoulder.
Closer's editor said the couple was "visible from the street".
A royal spokesman described the photographs as a "grotesque invasion of privacy".
"Their Royal Highnesses had every expectation of privacy in the remote house. It is unthinkable that anyone should take such photographs, let alone publish them," said a St James' Palace official, adding: "The incident is reminiscent of the worst excesses of the press and paparazzi during the life of Diana, Princess of Wales, and all the more upsetting to the Duke and Duchess for being so."
Within hours of the snaps being published, the royal couple announced they were launching legal action against the magazine.
"St James' Palace confirms that legal proceedings for breach of privacy have been commenced today in France by The Duke and Duchess of Cambridge against the publishers of Closer Magazine France," the royals said in a statement to BBC News.
Lawyers representing Prince William and his wife Kate are to appear in a Paris court today in a bid to prevent further publication of the topless photos.
St James's Palace says lawyers will seek an injunction against Italian media group Mondadori, publisher of both France's Closer and Italy's Chi gossip magazines, according to the Associated Press.
The palace will file a criminal complaint against the photographer who took the snaps, and also seek damages from the publisher.
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."
'OF COURSE PEOPLE ARE GOING TO BE INTERESTED IN THIS'
Palace officials also slammed the decision of the Irish Daily Star newspaper to publish the topless snaps on Saturday.
The Dublin-based tabloid ran a blurry reproduction of the pages from Closer over two inside pages in its Ireland edition, but not in its Northern Ireland or British editions, according to the BBC.
"There can be no motivation for this action other than greed," a St. James's Palace spokesperson said of the Irish tabloid's decision.
Editor Mike O'Kane defended his newspaper, telling the BBC that he was "taken aback" by reaction to the story in the UK.
"The Duchess would be no different to any other celeb pics we would get in, for example Rihanna or Lady Gaga," he said.
"She's not the future queen of Ireland so really the only place this is causing fury seems to be in the UK, and they are very very tasteful pictures."
He said the newspaper ran the pictures as a "service to our readers".
"She's married into the royal family, she's one of the most photographed people in the world, and she decides to partially disrobe on a balcony where it can be seen from a public road and she's stunned now, or the Palace are annoyed that people are interested in this.
"Of course people are going to be interested in this," he said.
Northern and Shell, co-owners of the Irish Daily Star, said they "abhor" the newspaper's decision to publish the snaps.
"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," the company said in a statement.
"Northern and Shell is profoundly dismayed at the decision made by Irish Daily Star, which would never have been made by any of the newspapers or magazines under our editorial control.
"We consider all aspects of privacy very carefully, and would never condone this action."
'COURT SCANDAL: THE QUEEN IS NUDE!'
And now the duchess faces further embarrassment as gossip magazine Chi said it planned to publish a 26-page spread with the photos on Monday.
Both Chi and the French edition of Closer are owned by former Italian Prime Minister Silvio Berlusconi's Mondadori media group.
Chi Editor-in-Chief Alfonso Signorini told CNN the magazine's front cover will feature three topless shots of Kate, under the headline "Court Scandal: The Queen is Nude!"
"It is a story worth publishing in an extraordinary edition because it shows in a natural light the everyday life of a very famous contemporary young couple in love," Signorini told CNN in an email statement on Saturday.
"The fact that they happen to be the future king and queen of England certainly makes it more interesting and current, and in line with today's concept of monarchy."
He also said he didn't fear legal action from the royals since the snaps were already in the public domain.
"Closer's position is different, they were the first ones to publish," he explained to the Associated Press.
"I don't see anything morbid or damaging in them," he said. "Chi pays attention to respecting people's dignity. I don't think they hurt Kate's image."
According to the Daily Mail, Signorini tweeted that "not even a direct call from the Queen" would halt him from publishing the snaps.
"I am convinced by this scoop that Chi will be publishing on Monday because that is what we are talking about. These pictures are not offensive or in poor taste, they are not morbid and they do not damage the dignity of anyone," he's quoted as saying, according to the Mail.
"Instead the pictures that were published in Britain of Prince Harry were exactly that - if I didn't recognise the journalistic value of what I had then if I did not publish them I would be better off in a market selling artichokes.
"These pictures were taken while the couple were on a terrace and they were taken from a public place so there is no suggestion of an invasion of privacy.
Palace officials said they were reviewing "all proportionate responses" to Chi's planned publication of the topless snaps.
"We will not be commenting on potential legal action concerning the alleged intended publication of the photos in Italy save to say that all proportionate responses will be kept under review," a spokeswoman said.
"Any such publication would serve no purpose other than to cause further, entirely unjustifiable upset to the Duke and Duchess of Cambridge, who were enjoying time alone together in the privacy of a relative's home."
The photo controversy surfaced just a few weeks after William's brother, Prince Harry, was embroiled in a nude snaps scandal after his flesh-flashing exploits in Sin City.
Webloid TMZ published grainy snaps of the cheeky royal frolicking naked during a game of strip billiards in a Las Vegas hotel suite last month.
Meanwhile, Kate and Wills shook off the topless snaps furore over the weekend by scaling a 130-foot tree in a Borneo rainforest.
Following their trip to Malaysia, the royal couple travelled to a rainforest in Borneo to visit the Danum Valley research centre in Sabah, and was snapped strapping on harnesses and being hoisted up a rainforest tree.
"I'm going to go 'whee' and just fly up," joked Kate, according to People.com.
A "playful" William quipped to his wife: "Girls don't have the same wardrobe malfunctions as men do. I hope I don't have any wardrobe malfunctions."
"Their royal highnesses are feeling upbeat, they are enjoying the tour and they will not in any way allow what has happened in France to overshadow the tour and their work on behalf of the Queen," a palace source told the mag.
FAST GOSSIP
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