The film was basically shot without sound because the crew had no access to electricity on location and therefore had to use noisy generators. The sound was later added in ADR sessions.
Five days were originally scheduled to shoot the film. After the first day of shooting the leading actor informed the director he had to leave in two days. So the film was completed in only three days.
The scene in the trash container was not in the script. It was improvised as they went along.
The actor who was intended to play the homeless guy dropped out the day before shooting. So the director asked Xaver Wiesholler, the actor who plays the cleaner in the film, to take the part. His pseudonym John Bensen is used in the credits.
14 Takes were shot on the scene were Lehmann jumps over the edge of the wall. They used the first take in the final film.