Or he might just be spelling it phonetically -- "Mrs." is prounounced "Misses" or "Missus" or sometimes "Mizzes."
In reality, though, "Mrs." is an abbreviation for "Mistress." Now this, if the translation held, would give "Madame" overtones of bondage, which could be why Alizée rejects the term for herself. Or, perhaps, reserves it for private use only. One never knows.
(Just kidding here, of course. "Mistress" in French is actually "Maitresse," not "Madame.")
