Darryl Zanuck behaved very badly on the set according to director Fleischer. He was not only there for scenes involving girlfriend Juliette Greco but for the other actors as well - including rehearsals. He sat in his chair smoking a cigar but not looking up from the script ON the set, something that Fleischer had never seen before or since. If an actor had to move, he had to move around Zanuck.
Despite the fact that Dublin was chosen because of its grey skies and regular rain showers, the weather during the shoot was unseasonably good, and Dublin fire crews were needed to hose down key locations to make the streets look wet!