Michelle Pfeiffer was offered the role of the Marquise de Merteuil in Valmont (1989), but she chose to play Mme. de Tourvel in this film instead.
Alan Rickman made the role of Valmont famous in London and on Broadway. However, filmmakers wanted to cast an established actor in the role, so Rickman wasn't even considered. Rickman ended up making his Hollywood debut as Hans Gruber in Die Hard (1988) instead.
When the novel "Les Liaisons Dangereuses" by Choderlos de Laclos was first published in 1782, it was considered so scandalous that when Queen Marie Antoinette commissioned a copy for her personal library, she had to have it bound in a blank cover so that no one would recognize the author's name or title.
Glenn Close was unavailable until midway through filming due to having just given birth to her daughter.
The red-heeled shoes seen at the beginning of the film are accurate to the fashion of this period of French history. Supposedly, King Louis XIV's brother accidentally stained his heels with blood one night attending a ball at a slaughterhouse. King Louis, taken with the aesthetic, ordered the royal shoemaker to imitate the look and paint all his heels and soles red, and it quickly became a popular fashion statement.