If she loses this court case, then the precedent is set - we can all look forward to pictures and videos being taken of us in our private spaces without our knowledge and consent, and being made available to the public and we will have NO legal recourse
But easily seen by a pap. So not private
*STOP comparing this to ordinary people in their gardens
- nobody would give a flying fuck about any of you sunbathing topless in your gardens
- pictures of you wouldn't be worth a fortune
- you're not paid for by the public purse
4)you won't be queen one day*
None of these is an accurate reflection of the actual, current law on misuse of private information though. If the D of C loses her case (in France) it is not going to change the legal position in Britain, where what happened to her would be a civil wrong for which she could get an injunction, and damages.
The fact that someone (especially someone using a very powerful telephoto lens can see does not mean that where you are is not private. The law is a bit more nuanced than that, I think.
Across all the countries that have signed up to the European Convention on Human Rights, people effectively have a right to a private life (i.e. a privacy right). Even famous people and royals. There is no standard public figure get out for the media like there is in the US. So her situation being papped in a private garden is broadly comparable to the situation if any of us got papped, i.e. wrong.