Gert Fröbe's performance in this film prompted Harry Saltzman and Albert R. Broccoli to cast Fröbe as Auric Goldfinger in the James Bond film Goldfinger (1964).
Friedrich Dürrenmatt wrote the screenplay (together with Hans Jacoby and Ladislao Vajda) while developing the novel form of the story under the title "Das Versprechen" (The Pledge). He finished the novel after the film was completed and gave it a different, much darker ending.
French-speaking actor Michel Simon, who plays Jacquier the peddler, learned the German dialogue phonetically.
Ewald Balser plays Professor Manz in the German language version, but Roger Livesey plays Professor Manz in the English language version.