The part of Elizabeth Roffe was turned down by Candice Bergen, Jacqueline Bisset and Diane Keaton before Audrey Hepburn accepted, and the character's age was changed from 23 to 35.
Exotic settings featured in the movie included Sardinia, New York, London, Munich, Paris, Rome and Switzerland. The picture was shot in at least seven cities in six countries, the latter being Italy, England, Germany, France, Denmark and the USA.
In Sardinia, when Major Campagna talks to his soldiers, he speaks in Italian, but when he talks to his superior, on the phone, he speaks in English and not in Italian.
As Elizabeth prepares for her first meeting at Roffe, we see the board of directors waiting for the meeting to start...but the shot is taken from a later scene and shows them with different outfits, hairstyles and seating assignments than when the meeting starts a moment later.
When Elizabeth Roffe and Rhys Williams are in the hotel room, she left the bathroom in a nightgown after a night of love, but he is in jacket-and-tie with a overcoat in the arm.