In Vivre Sa Vie, Nana's face operates is both a rigid network and a more floating one. Her subjection to a number of repressive apparatuses--the police interrogation, the rules of the pimp--as well as her subjectification as woman and then prostitute may be a textbook Althusserian take on identity, if it weren't for the fact that these cliches of power imposing itself on a person are subsumed by the powers of another reality. While, with the good humor of a "lady," she exists in these networks of (mostly male) power, we always have the sense that her pleasure is outside. Frequently, she seems to fall in love with glimpsed strangers, and she is adept at taking her enjoyment into her own hands (as in the dance scene at the pool hall).
The crucial scene in which she sees Dreyer's Passion of Joan of Arc drives home the fact that Godard's film is a study of the face and its framing. It also gives us the sense that Nana, when framed for close-up or smiling for her pimp, is at that moment a happy martyr, who will only experience a life that could be called "her own" as a mystic does transcendent mysteries.