Scaramouche

As has been commented by the other two people, the final sword fight makes the movie (although it is not the only reason to watch). It runs non-stop for over 7 minutes. One interesting point is that aside from the leap from the staircase to the floor below, Granger did all of his own stunts in the sequence (including swinging from the stage into the opera box and dangling over the audience early in the fight). The only fight that comes anywhere near it is the one between Danny Kaye and Basel Rathbone in "Court Jester".