I think you were talking about this, well, thing(sorry, don't know how to say in english
I once read it was made by Karl Lagerfeld (close friend of Caroline and Ernst August) specially for her, don't know if it is true. Karl also made her 18th birthday dress. It is grey and there are only paparazzi pictures of it. I've seen one here, recently, Charlotte walks up the hill to her party with some friends.
(pictures are probably from the modern jet set groups)
about Felix: Winckler is a German/Austrian name, but antoine is french/belgian, so he needn't be German, maybe he has just german ancestors. Once someone at theroyalforums found a "work" in the internet of someone who's name is Felix Winckler and who studies law in Münster, Germany, but this person is IMO a little bit too old to be Felix and as we know, Felix lives in Paris.
-but I'd find it very interesting if he is german,
former boyfriends of Charlotte (Hubertus Herring - Frankensdorf - these are only rumours!!!) are German/Austrian, too. It is probably because her stepbrothers are german and introduce her to the guys.
Today i've read that Charlotte's course is called "Hypokagne", A preparation cours for the higher school, but I don't know exactly what it is.
About her brands: I've read that she likes Chanel, prada, ralph Lauren, givenchy.
This top is from Morgan de toi.