The film has no score. The only music in the background is that of an ice-cream truck passing by outside the window.
All dialogue was improvised while shooting. There was a plot but no screenplay.
The scene with Karl telling Inge the joke was supposed to be different. Karl was supposed to tell a dramatic story from his past, but after the scene was shot three times, director Andreas Dresen still thought it didn't feel right. Instead he told actor Horst Westphal the joke, who didn't find it funny at all. When he tells that joke to Ursula Werner in the film, she is hearing it for the first time so the laughter is genuine.
The correct German translation for "Cloud Nine" would be "Cloud Seven", but the director liked the number "9" in the original title better, which he took from a Beatles song. He also once joked about naming the film "Cloud Eleven" when it would be released in English-speaking countries, thus remaining the in-joke.