In the earlier scene Hotte Ehrenreich is watching Der schwarze Kanal (1960). The colorful intro with the German anthem as the theme music, which is shown on TV was in use since 1979. The movie however is set in 1973.
On the Black Sabbath-poster in Micha's room the guitarist Toni Iommi is seen with drummer Cozy Powell. He didn't join Black Sabbath until 1989. The movie however is set in 1973.
The Ehrenreichs are watching Am laufenden Band (1974) on TV. The show premiered in 1974, while the movie is set in 1973.
The Rudi Carrell-song "Eine Insel für mich allein" was released in 1978, 5 years after the movie's setting.
The title sequence voiceover refers to John Lennon's death, but he was not killed until 1980.