When Bugs is making Francois to look like a rabbit, Francois' whiskers disappear for a moment (just before Bugs holds the glassless mirror between him and Francois).
Once Bugs Bunny lights the wick the fuse burns to the oven doors edge then the dynamite explodes even though the fuse would still have a while to burn thru before exploding, based on the original length of the fuse.
At the end, Louis and François are singing "Alouette". However, that is a Canadian song.