The only double the producers could find for Christopher Lee was the circus' real lion tamer, who Lee described as being "half my height". In order to make the situation credible, 6'4" Lee was shot in close-up, so the height differential would not be too obvious to the audience. According to Lee, he wore a black mask through 90% of the movie anyway.
Barberini's circus' winter quarters were largely filmed in Winkfield, Berkshire, the real-life home of Billy Smart's circus, one of Britain's most famous circus companies.
Though shot in color, the film was released in Germany in black-and-white. Rialto Film, the production company of the German Edgar Wallace series, was very close to Constantin Film, this movie's German distributor and co-producer. Rialto wanted to promote a production of its own as the "first Edgar Wallace film in color". That was Der Bucklige von Soho (1966), released in Germany only a couple of months after this film. The original color version was released in Germany on DVD in 2006, though in edited form.
The 1967 US release was in black-and-white and edited down to one hour and five minutes for bookings on the lower half of the bill.
The Miracle Pictures bargain DVD release prominently features Christopher Lee on the cover. The image of Lee is from a later film, "The Man with the Golden Gun" (1974).