The publisher and photographer of unauthorized topless snaps of Prince William's wife Kate have been placed under formal criminal investigation by French prosecutors.

Caroline Chassain, a spokeswoman for the French prosecutor, said that Mondadori Magazines France and photographer Valerie Suau have been placed under investigation over possible criminal exploitation of the images, which appeared in the French 'Closer' magazine last September.

The series of photos showed the Duchess of Cambridge relaxing topless at a private villa in Provence in southern France and in one case with her suit bottom partially pulled down to apply sunscreen.

According to the Huffington Post, Chassain added that Suau's employer, the local newspaper 'La Provence' was also placed under formal criminal investigation, which will likely take months to complete.

The blurry photos shocked the public and have been called a 'grotesque and totally unjustifiable' abuse of privacy by British royal officials.

Although Prince William and Kate made efforts to halt their use last September they went on to be published in Italy, Ireland, Sweden and world wide on the Internet.

No major British publication has carried the photos, including Rupert Murdoch's top-selling tabloid The Sun, which did however publish photos of a naked Prince Harry cavorting in a Las Vegas hotel room last year.

Kate Middleton, Duchess Catherine of Cambridge,Google Images