The picture was taken during Kate’s recent tour of Australia when a gust of wind briefly caught her dress – and her flimsy underwear did not offer much protection.
Now tabloid newspaper Bild am Sonntag has published the image beneath a series of tasteless headlines.
It ran the photograph alongside pictures of US reality television star Kim Kardashian and her sister Khloe, famed for their shapely bottoms, with the caption: ‘Khloe, Kim and Kate – backsides which have moved us these past few days.’
The breach of privacy comes less than two years after the Duke and Duchess launched legal action against a French magazine that printed topless photographs of Kate on holiday.
The latest photograph was taken as the Duchess boarded a helicopter to Sydney after an official tour of the Blue Mountains with Prince William last month.
The couple had been visiting Winmalee, a small community where 195 homes were destroyed in the worst bush fires in a decade, as part of a three-week tour Down Under.
As the wind from the helicopter’s rotor blades lifted Kate’s £295 Diane Von Furstenberg wrap dress, an opportunistic photographer captured the moment and touted it around international newspapers.
It was reportedly sold to the ‘highest bidder’ after British papers refused to print it.
First published in the Bild’s Sunday paper, it also appeared on its website, accompanied by crude captions.
Beside the offending picture were the words: ‘Thank the wind for the insight into the royal household.
‘On Sunday, photos appeared which show our favourite Duchess Kate, 32, in the Australian Blue Mountains.
‘The royal helicopter rotor blades swirled up the air so that Kate’s summer dress began blowing upwards – affording us a glimpse of her beautiful bum.
‘Never have we been so thankful to a helicopter for creating such a wind.’