Noémie's a social climber who makes no bones about the fact. She comes across as sweet and innocent, but that sugary exterior hides a ruthless moneygrubber.
When Newman first stumbles across her at the Louvre, he's struck by how well she makes copies of paintings. But when Noémie meets Newman, she instantly sizes him up as a business opportunity.
Even Noémie's father, M. Nioche, recognizes her for what she is: a "franche coquette" (4.33). That is to say, she likes to flirt a bit when it's to her benefit.
But Noémie prides herself on being honest even when she's flirting, giving just a little edge to her every interaction with Newman. When Newman asks for her address after first meeting her, she gives it willingly with a wink:
"Happily for you, you are an American! It is the first time I ever gave my card to a gentleman." (1.27)
In other words, Noémie wants Newman to know that she's less naïve than she might initially seem.
Judging by the way Valentin and Stanislas Kapp fall head over heels for Noémie, she has no problem finding a date. A besotted Valentin calls her "remarkable," even as she takes up with another older gentleman (15.2). That's devotion, folks.
Noémie owns the femme fatale label and ends up strutting her stuff with some serious pride, much to the shock of Newman.