Yes, it is. It's really a trivial matter, save for the security lapse. It would be nothing as a story in France itself, but for the foreign interest.
How big an intrusion into privacy would it have been if she had had her top on ? Not as bad ? If so, why? . It's with an eye to the non-French market that these were published, a view to getting foreign profits. The French are very interested in our Royals and all they do: whether the Royals are topless or not, whether in public or in private, makes no difference. French women started sunbathing topless, in public, long ago. We still seem to think there's something a bit naughty or daring about it in this country, that it's something only to be done in private and secretly here, and so these photos are doubly offensive to us as a breach of privacy.