Demimonde

[Sarah]

Persons of doubtful reputation; esp., women who are kept asmistresses, though not public prostitutes; demireps. Literarydemimonde, writers of the lowest kind.

[Britney]

(in 19th-century France) a class of women considered to be of doubtful social standing and morality.

[Sonia]

(french) literally half world, [the English] equivalent would be [underworld]. It is important to note that the final e is not pronounced in accordance with rules of french pronunciation. Has a [pretentious] ring to it.