The cast is composed mainly of first-time actors, most of whom were still in school at the time and have mostly not pursued acting careers since. Natja Brunckhorst is the only cast member who continued to act in German films and television, starting with 1982's "Querelle" by Rainer Werner Fassbinder, at the time the highest-grossing film with a strongly homosexual theme. Most of the extras at the railway station and at SOUND were actual drug users and prostitutes. In the scene where Christiane runs through the alleys of the station to find Babsi, the camera lingers on several drug users leaning against the walls of the underpass. In a 2011 interview, Thomas Haustein, who played Detlev and was still in school at the time, recalled how terrified he felt being surrounded by real-life addicts, but that he was able to successfully copy their behaviour for his character. It would now be illegal to have minors act in the film's graphic shoot-up, nudity and sex scenes; at the time, however, all the production needed was a written letter of consent from the parents to proceed with filming.