The Man in the Iron Mask (1998)

Other mistake: When the Musketeers are charging the firing squad at the end, they only have about 20 yards to run which they should cover in just a couple seconds, but somehow it takes them much longer to reach the other men. This is especially noticeable since they're running at full speed. (This has nothing to do with editing or slow-motion, as most of the shots are shown in real time, at regular speed.)