The good news is I recently stumbled across La Bonne Soupe on Youtube. The bad news is I can't understand a word of it. La Bonne Soupe is a 1964 French film that features Franchot in a character part. This foreign film is definitely a departure from the majority of his filmography, but I welcome any performance of Franchot's (even when I'm clueless as to the dialogue!). I'd love to get my hands on a version with English subtitles.
The film seems quite funny and Franchot pops up unexpectedly in several scenes.
In the cinema column, "Capsule Comments", in the Toledo Blade newspaper dated November 1, 1964, La Bonne Soupe is described as "a merry, bawdy French comedy about a girl of easy virtue and her search for Easy Street". Here is Bosley Crowther's review of the film in the New York Times.
Below is the Youtube video. If it doesn't play correctly from my blog, try this direct Youtube link. Franchot enters the picture at about the 5:15 mark and reappears throughout.