Douglass Dumbrille is credited as "Douglas Dumbrille" in the titles.
The movie is set in Paris, but as is typical of the era, none of the principals even attempts a French accent. George Barbier's Philadelphia "honk" in particular sticks out like a sore thumb.
Someone as "highly intelligent" as Francoise would not have disposed of the murder weapon in a bucket of water, where someone would be sure to find it.