So ein Flegel (1934)
So ein Flegel is a 1934 German comedy film based on the novel Die Feuerzangenbowle. It modifies the story by introducing the concept of two brothers Pfeiffer switching places: While the younger brother takes over his elder brother’s job, the older brother attends the younger one’s school. Heinz Rühmann starred in the double role of the brothers Pfeiffer in this lesser known movie a decade before playing Hans Pfeiffer in the more popular 1944 version.
More at Wikipedia.