This 1993 film adaptation of the famous historical drama/mystery stays well to the original story.
Perhaps the most recognisable faces are Uwe Ochsenknecht and Katharina Thalbach. We also see Udo Samel (Mein bester Feind, Die Klavierspielerin) and Hermann Beyer (a very busy actor, recently of Dark fame), among many others.
It is, of course, not the only film adaptation of this mystery. In 1969, a team of 10 directors took on the story and created a three hour event. Werner Herzog did his own version in 1974, which does not include the sexual innuendos that exist in the 1993 version. There was an Italian version released in 2012, which may be of interest to those more interested in the historical drama aspect than German film.
This version may not be appropriate for most classrooms, and the story would not be as comprehensible without showing the film in its entirety.