This short was meant to expose the horror and terror of French slaughterhouses in the 1920's. For this reason, it is an important film, but obviously a very violent and gory one as well. Animals are murdered brutally and graphically. Not for the faint of heart at all.
Horses, sheep, bulls, etc. get decapitated, axed and shot. Lots of blood gushes out of the animals, which, even though is in black and white, is nonetheless still quite disturbing. Some animals twitch after they've been murdered, and it's all the more horrifying that the workers do it so casually.