Despite being fluent in German, Renée Soutendijk was dubbed by Hannelore Elsner in post-production due to her noticeable Dutch accent. In some scenes, Soutendijk's real voice can be heard for a moment.
Film debut of Hannes Jaenicke. Director Carl Schenkel asked him to audition after he saw his performance at a theatre in Bonn.
For filming purposes, the elevator was partly rebuilt inside an old building in Munich. An entire staircase had to be removed in order to make room for the set.
Most of the film was shot inside the European Patent Organisation in Munich.