Director Tinto Brass claimed that the actresses who play the prostitutes in Kitty's brothel were all very enthusiastic about their characters. He has said that they told him that liked being able to explore that side of their own personalities.
Ken Adam began work on this film immediately after production wrapped on Barry Lyndon (1975). He had found working with the previous film's director, Stanley Kubrick, suffocating due to Kubrick's obsessive attention to period accuracy and tendencies to micromanage. Adam was, by contrast, very happy to create the sometimes quite stylized sets seen in this film.
In the English-language version of the director's cut, the restored footage (with the prison cells, the sex circus beforehand, and a few other graphic sexual scenes) is in Italian. This is because these scenes were not included in the original, censored English version and only the Italian soundtrack exists.
In his own words, Tinto Brass considers himself 'the King of Mirrors' as he knows how to film mirrors without the camera being seen on film. This is why the movie is thoroughly infused with frequent mirror images of his leading lady and the other actresses as well.
German actress Brigitte Skay was originally cast as a Hungarian countess but refused the role after Tinto Brass asked her to show him her backside. Consequently the character was written out of the movie.
After the girl who is foaming at the mouth is brought away, Teresa Ann Savoy is seen wearing a dress that is a near exact copy of one Joan Crawford wore in Grand Hotel (1932). The original Crawford dress had been designed by Adrian.