This is the first Dutch English spoken film.
Although the film is set in the Netherlands (particularly Amsterdam), and all written texts seen in the film are in Dutch, the original spoken language is English.
Conceived as an homage to Rear Window (1954), the film was scored by Alfred Hitchcock's frequent collaborator, composer Bernard Herrmann. It is said this was done on suggestion of the filmmaker and Hitchcock enthusiast François Truffaut.
The first German-Dutch co-production since the Second World War (1939-1945) in which Germany occupied the Netherlands.
Italian censorship visa # 56024 delivered on 2 May 1970.