More about her father can be found on [Wikipedia] (several languages) and on [IMDb].

[Das] Gélin was married when he had an affair with the then 17 year old Marie Christine Schneider.

[Hmnt1994] Maria Schneider met her father only three times in her life, and he never recognized her.

[CV4Ub] She had declared, and that was the very truth, that she was the natural daughter of the actor Daniel Gélin, who was in the early 1970s still infinitely respected and popular.
So, everybody came down on her calling it a lie, even an defamation! And the first to run with the pack was Daniel Gélin himself, who red with rage answered the journalists who talked about the ‘Maria Schneider affair’: ‘She starts to grate on my nerves, this little pest! I only have one daughter and that is Fiona, born in 1962, all the rest is a mere invention of that girl, who with her lies makes people talk about her and even got a few small film roles’. Another magzine headlined: ‘The wrong daughter of Daniel Gélin declares to be prowd of the father she claimed but did not extend the insult to calling herself Maria Gélin’.

[IMDb] claims that the mother (named Christine Marie Schneider) acted in the movie The nutcracker (2001) by Glen Grefe

[Das]: mother was only 17 or 18 when Maria Schneider was born

[wikipedia F]: mannequin, romanian

[BuetJ]: mother was librarian in Paris (at the time of Maria’s birth)

- had a half-brother Xavier Gélin, 1946-1999
 - had a half-brother Pascal Gélin, 1956-1957
 - has a half-sister Fiona Gélin, 1962-
 - has a half-brother Manuel Gélin, 1958-
 - has a half-sister Laura Gélin, 1975-
[Hmnt1994]: her mother has also more children, with whom Maria has good contact
[JB]: has an uncle Georges Schneider