I've been re-reading
Le Cinéma X, a book by Jacques Zimmer, published by "La Musardine", and taking notes. It's a pretty good encyclopedia of porn published in 2002 and it remains quite instructive on several points, even though big parts of it are inaccurate now that we have better sources of information such as EGAFD and the like.
Gambier's bio included a bit of information that I had to check out : according to Christophe Lemaire, who wrote most of the bios, at the same time she was appearing in porn movies, she also appeared on French TV in a TV commercial for the chocolate brand "Kit Kat" (an equivalent of sorts to Marilyn Chambers' "Ivory Snow", in a sense).
I checked out on a French tube site devoted to TV ads and found something that might confirm what Lemaire wrote. Captions are enclosed, and a side-by-side comparison with Karine from her movie "Queue de Béton".
If you want to see the TV ad, just type the following words on google video search and you'll find it immediately :
"les adultes croqueurs de kit kat"
Is it the same girl? You decide...