Fleur was a Global Guardian, who went freelance and has since popped up in a couple of random places, and is apparently Deathstroke's ex.
I always thought she'd be a good fit with Checkmate, and I kind of think Rucka missed an opportunity when he added Marie to the DCU when Noelle was right there being French and badass and having familiarity with intelligence work already, and also has very cool weaponry.