A French court's ruled a celebrity magazine must pay €100,000 in damages to Britain's Kate Middleton and Prince William.

It's after Closer published topless photos of Kate, which were taken while the couple were on holiday in 2012.

The magazine's editor and owner must also each pay €45,000 in fines.

In a letter read in court, Prince William said the case reminded him of how the paparazzi hounded his mother.