The title is a reference to "The Communist Manifesto," which in English begins: "A spectre is stalking Europe, the spectre of Communism." The French translation known to Buñuel translated "spectre" as "fantôme." So, the title can be seen as a dig at the "Bourgeois" mentality which fears freedom, and also a sideswipe at the rather straightjacketed Communist parties of the time.
In British broadcasts the "Serial Killer as Celebrity" segment is often cut out.
Director's trademark: [insects] Foucauld places a large framed spider on the mantelpiece after declaring that he is "sick of symmetry."
The painting hanging in the office at the police station is Francisco Goya's "The Third of May 1808," which was inspiration for the opening scene of the film.
In this movie Adriana Asti has a nude scene, where she plays the piano dressed only in a pair of stockings and patent leather shoes. She recalled the first meeting with Luis Buñuel:"To make sure he liked me before we started shooting, I showed up in his dressing room with a Valentino raincoat lined with fur. I took it off, I had nothing underneath. 'Voilà, je suis comme ça', I told him. He was almost embarrassed, he looked like Pasolini, simple and sublime. 'Madame, s'il vous plait, je suis pas un pornographe', he replied."