Mae West was originally offered the role of Madame Coco La Fontaine but the producers refused to let her write her own dialogue, so the part went to Ethel Merman.
The sketches and works of art that Dick Van Dyke was working on in the "Art of Love" were actually done by Alto, Louisiana native Don Cincone, an internationally acclaimed expressionist. In 1968, he was awarded the Silver Medal of Literary Arts and Sciences in Rome and his work has been collected by Walt Disney, Kurt Schon, Henry Mancini, Ross Hunter, James Garner and Vincent Price! Although he was never credited for his artwork in the movie, he still speaks fondly of his "Hollywood days" and the impact that it made on him.
When "The Art of Love" was in theaters in 1965, France still had the death penalty, carried out by guillotine. The last person guillotined under the death penalty there was in 1977. A 1981 law repealed the death penalty in France.
According to Yves Boisset, who was an assistant to Norman Jewison and guided him in Paris, Jewison did not care about the Paris realism, about the settings which were shown as old fashioned cliches.
Dick Van Dyke's character in The Art of Love is named Paul Sloane. Decades later, he would play Dr Mark Sloane in Diagnosis Murder (1993).