Balthazar was an untrained donkey during most of the filming, which made Bressons's work a real challenge. The only scene for which the donkey was trained was the circus math trick.
When Balthazar is shot he is facing to the right of the screen, and Gerard runs away from him indicating that the shooter is somewhere left of Balthazar. When Balthazar appears next he is bleeding from his right side.
The "for Sale" sign that is on the fence when Balthazar runs through the gate is different to the one seen in close-up. Also, when he runs through the gate, the sign is in shadow but in close-up it is in full sun.