The famous swimming pool orgy sequence set in Paris, France was actually filmed at "The Sanctuary", a private women's health and spa club in Covent Garden, London. It closed in 2014.
When this movie became successful at the box office, Jackie Collins went out and wrote a book sequel to her novel "The Stud", titled "The Bitch". The books were published about a decade apart, in 1969 and 1979. A movie of the sequel, The Bitch (1979), was made pretty much straight away. Whereas the first movie had taken almost a decade to get made from the time the novel was first published, the sequel had no delays in getting filmed at all.
Dame Joan Collins once described this movie as " . . . a rather erotic and sensual story, but sophisticated, like Shampoo (1975) or Alfie (1966). Ever since I read the book, I have wanted to play Fontaine. She's the arch-bitch goddess, but there's another dimension. There's a lot of sadness there, and a lot of pain."
This movie was released nine years after Jackie Collins' source novel "The Stud" was published. This movie's production stated that the novel had been "too hot too handle" and that it had taken several years for public attitudes towards sex to relax enough for this movie to be made.