This is unprecedented. It would be a mistake to underestimate the real sense of fury that these pictures have generated.
There have been legal warnings before, editors warned off before - even a cash settlement to the Middletons over private photographs of Kate taken by a German photographer.
But this one is going all the way to court.
It's made worse for William by the fact that this is the French press, who he still really blames for the death of his mother.
All of this may include a look at how Royal protection works. William and Kate were visible, somebody did see them and somebody got a lot of photographs.
It raises questions not just about privacy but also about security.
SE og HØR has boasted of "exclusive" access to the "topless pictures of Great Britain’s future queen", which hit Danish newsstands tomorrow.
A court in France has blocked French magazine Closer from re-publishing images of the Duchess of Cambridge sunbathing topless.
See some of the highlights of the Duke and Duchess of Cambridge's tour of the Solomon Islands.