Cherchez la femme

I often wondered what the source of the phrase "cherchez la femme" was - "look for the woman," often repeated in noirs and detective fiction; I always assumed that came from some French New Wave cinephile - a critic or filmmaker - in reference to American cinema or genre fiction, then was incorporated into the same. Encountering it in Roman Polanski's Chinatown, this evening, however, I realized the source had to be earlier, since Faye Dunaway uses it with Jack Nicholson - in a film set in the 1930's that has reasonable attention to period details. It provoked me to finally scratch this itch, looking up the phrase on Wikipedia. The page for it explains that it comes from a 19th century French novel by Alexandre Dumas. Who knew?