“I knew the dame was trouble the moment she sat on the whoopie cushion.”
Noir actually seems like it’d be a good fit for a clown. When I think about a noir protagonist, I picture a beaten-down man who struggles to live another day only because he’s too tired to die. I think, basically, of cynicism personified. And really, is there anything more cynical than a man whose face can only muster a smile if it’s painted on?
Besides, if there were a clown in a noir, he’d have to get beaten up quite a bit, and the thought of a clown getting punched in the stomach is bound to make somebody smile.