The 15 first names begin with O

Octave Christophe Arnaud (1)
Octavie (1)
Odette (4)
Odile (9)
Olga (1)
Olive (23)
Olivia (1)
Olivier (47)
Olivier Georges Henri (1)
Ollivier (3)
Olman (1)
Ondine (1)
Ophélie (1)
Oskar (1)
Otto (1)