The Duke and Duchess of Cambridge are demanding €1.5m ($AUD 2.1 million) in damages from those responsible for taking and publishing topless photographs of Catherine.
A statement from Prince William was read at the trial of six people — including three photographers — accused of invasion of privacy and complicity.
“My wife and I thought that we could go to France for a few days in a secluded villa owned by a member of my family, and thus enjoy our privacy,” the statement began.
“We know France and the French and we know that they are, in principle, respectful of private life, including that of their guests. The clandestine way in which these photographs were taken was particularly shocking to us as it breached our privacy.”
He added that the images were “all the more painful” given that his mother, Diana, Princess of Wales, died in a car crash in 1997 as she was being pursued by photographers.
William was just 15 and his brother Prince Harry only 12, when Princess Diana was tragically killed in a car crash in Paris on 31 August 1997.
Paris-based agency photographers, Cyril Moreau and Dominique Jacovides, have both denied any wrongdoing.
The others accused are Closer’s editor Laurence Pieau, Ernesto Mauri, chief executive of the Mondadori group which owns the magazine, La Provence photographer Valerie Suau, and Marc Auburtin, the paper’s publishing director at the time.
The photos, which were captured via long-lens as the couple holidayed in the south of France, were featured on the cover and inside pages of France’s Closer magazine and in the regional daily paper La Provence in September 2012.
The couple were pictured applying sunscreen and sunbathing on the terrace of a private residence owned by Viscount Linley, the Queen’s nephew.
The Duke and Duchess of Cambridge recently made their first official trip to Paris.
Kensington Palace issued a statement at the time describing the incident as “unthinkable.”
“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,” the statement read.
“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.”
A verdict is expected on July 4.
