The lawyer for two agency photographers, who only recently took over the case, obtained the four-month delay in order to prepare the defence.
The case relates to risque grainy snaps of the former Kate Middleton wearing nothing but a black and white bikini bottom while on holiday in September 2012 in the south of France with her husband, the second in line to the British throne.
They triggered a furious reaction from the British royal family and a furore in Britain where several newspapers had rejected an offer to buy the pictures.
After appearing in the French version of celebrity magazine Closer, the photos were reproduced in several other European publications such as Chi in Italy, Ireland's Daily Star and sister magazines in Sweden and Denmark.
The editor of Closer in France, the head of the Mondadori group which owns the magazine, regional newspaper La Provence's manager and one of its photographers, and two Paris-based agency photographers were due to go on trial on Tuesday charged with invasion of privacy and complicity.
Closer's editor Laurence Pieau defended her publication's actions at the time of the initial scandal, saying the pictures were not in the “least shocking”.
The magazine has always refused to divulge the identity of the photographer who took the topless pictures. Earlier in September 2012, the Marseille-based La Province had printed pictures of the Duchess of Cambridge in her swimsuit at a chateau owned by Viscount Linley, the son of Princess Margaret, the late sister of Britain's Queen Elizabeth II.
The royal couple launched legal proceedings to try to identify the photographer but La Provence denied its employee, who took the other pictures a week earlier, was the author of the topless snaps.
The Duke and Duchess of Cambridge's lawyer had argued that the photos were particularly distressing for the couple as it brought back painful memories of William's late mother Princess Diana's death in a road crash in Paris in 1997 while being hounded by paparazzi.
French authorities sided with the royal couple by banning any further reproduction of the pictures before launching a probe into how the snaps were obtained.
By Juliette Montesse