Fran is a boss in Final Fantasy XII: Revenant Wings.
Fran, along with Balthier, battles Vaan and his friends in the last mission for chapter 6. She frequently uses Confuse Arrow, which adds the Confuse status effect to her attacks, and Ward of the Wood, which heals both her and Balthier.
The best strategy against the two is to lure Ba'Gamnan, who also partakes in the battle, to attack Fran. After she falls, Balthier will be weakened and easily defeated.