Director Billy Wilder said famously of his difficulties with Marlene Dietrich and Jean Arthur in the film. "I have one dame who's afraid to look at herself in a mirror and another who won't stop looking!"
In a biography of her famous mother, Marlene Dietrich's daughter Maria Riva wrote, "She left for Hollywood in '47, quite sure that once she had designed the clothes, sung the Hollander songs, and made sure that 'Billy won't insist that the woman was really a Nazi during the war,' A Foreign Affair would become a Dietrich film."
When Billy Wilder arrived on location in Berlin, he saw that the city had cleaned up a little since he was there right after the end of the war, but the results of close to 400 Allied bombing raids were still very much evident. Nearly half a million of the city's buildings had been destroyed, and although resilient Berliners were finding ways to survive, food was still scarce, the black market was thriving, and military police were everywhere. Filming in this virtual war zone suited Wilder's purposes very well, since he needed to show a destroyed city in chaos.
Billy Wilder and his crew filmed throughout Berlin for nearly a month. Their footage appears as rear projections in several scenes of the finished movie. It also forms the basis of a typically sardonic visual joke: as Captain Pringle rides through the ruins carrying a mattress he bought for his German mistress on the black market, the soundtrack plays the sweet tune "Isn't It Romantic?"
Marlene Dietrich reportedly didn't think too highly of her co-stars, calling John Lund "that piece of petrified wood" and referring to Jean Arthur as "that ugly, ugly woman with that terrible American twang."
Upon completion of location shooting, Billy Wilder headed back home by way of Paris, where he stopped in to see Marlene Dietrich to convince her to take the part of the German cabaret singer and former Nazi official's mistress. Dietrich had spent most of the war travelling among Allied troops, justly lauded for her anti-fascist efforts, often at the front lines, popping back to the States only occasionally for movie roles. Her immediate reaction when Wilder brought his offer to her at the Hotel Georges V where she was staying was a quick and vehement no. She had no intention of playing a woman with a Nazi past, but Wilder wouldn't take no for an answer. He swayed her with the promise that her songs in the picture would be written by her old friend and frequent composer Friedrich Hollaender. One story has it that eventually he showed her screen tests of other actresses he claimed to be considering for the role and that did the trick (reportedly, one of them was June Havoc), although Wilder denied that such a ploy was ever used. More likely what swayed her was the fact that her screen popularity had waned and she needed a hit movie. It also helped considerably that she would be paid $110,000 with an additional $66,000 promised for overtime.
For the scene in which Phoebe character gets drunk and ends up being tossed in the air by rowdy soldiers, Billy Wilder wanted to use a double, but Jean Arthur insisted on doing it herself. After the physically strenuous take, she said loudly and pointedly, "What will you require next from me, Mr. Wilder," to a round of sympathetic applause from the crew.
Future director Gerd Oswald, then assistant to Billy Wilder, said it was rumoured that Marlene Dietrich was having an affair with everyone, particularly "a couple of muscle-men stunt guys she just devoured." John Lund called her a "mixture of siren and homebody, gracious, unfailingly professional and funny," and related a story about Winston Churchill's son, Randolph, making such a pest of himself pursuing Dietrich on a visit to the set that Wilder's wife finally threw a glass of wine at him.
Future Emmy-winning editor John Woodcock, assisting in the cutting of the picture, recalls a moment when Billy Wilder was reviewing the footage he shot in Berlin. Seeing aerial shots of block after block of levelled buildings, Woodcock remarked that he felt a little sorry for the Germans. Wilder jumped up in a rage: "To hell with those bastards! They burned most of my family in their damned ovens! I hope they burn in hell!"
Marlene Dietrich moved into Billy Wilder's house during production, and the two friends had a great time together, on set and off. She was always eager to oblige when Wilder prodded her about affairs with both sexes.
German-born film producer Erich Pommer had been placed in charge of the film section at the U.S. government's Information Control Division in Berlin. He helped the production by arranging for the recently reconstituted German film studio Ufa to advance the production's expenses in deutschmarks.
One of the big clashes Billy Wilder and Charles Brackett had on this picture was over Marlene Dietrich's first scene. She is introduced in her bombed-out shell of an apartment, brushing her teeth, and when John Lund comes near her, she spits in his face. Brackett was so offended by the scene and by Wilder's flippant defence of it that he threw a phone book at the director's head.
Mirroring the triangle in the plot of the movie, Jean Arthur and Marlene Dietrich vied with each other for Billy Wilder's attentions, with Dietrich usually coming out far ahead. Although this was their first picture together, the two Europeans were old friends, and they would frequently be off in a corner of the set, talking in German and giggling. Sometimes Wilder went to Dietrich's dressing room for lunch or tea. All of this had Arthur seething, compounded by the fact that she was always insecure about her looks and knew she was playing the Plain Jane to Dietrich's Glamour Girl in this film. Reportedly, she showed up at his house one night with her husband, producer Frank Ross, visibly shaken and eyes red from weeping. She demanded to know what he had done with a certain close-up of her, "the one where I looked so beautiful," and accused Dietrich of having forced Wilder to burn it. One story claimed he eased her concern by showing her the close-up, but Wilder always said no such shot ever existed.
While serving with the United States Army in Germany during World War II, Billy Wilder was promised government assistance if he made a film about Allied-occupied Germany, and he took advantage of the offer by developing this film with Charles Brackett and Richard L. Breen. Erich Pommer, who was responsible for the rebuilding of the German film industry, placed what was left of the facilities at Universum Film AG at Wilder's disposal.
Paramount had to get permission from the War Dept. in order to shoot in Berlin, and once there, had to deal with the Military Government for their needs. In addition, Paramount hired a German crew from Film-Studio Tempelhof, a division of UFA.
In filming the nightclub scenes, Paramount introduced a new "silent" method for shooting dance sequences: flashing lights were used on the set to denote rhythm so that dialogue could be recorded without the obstruction of music.
While researching the existing situation for his screenplay, Billy Wilder interviewed many of the American military personnel stationed in Berlin, as well as its residents, many of whom were having difficulty dealing with the destruction of their city. One of them was a woman he met while she was clearing rubble from the streets. "The woman was grateful the Allies had come to fix the gas," Wilder later recalled. "I thought it was so she could have a hot meal, but she said it was so she could commit suicide."
Billy Wilder persuaded Jean Arthur, who was attending college at the time, to come out of retirement to play Phoebe. Throughout filming, the actress felt the director was favouring Marlene Dietrich, and late one night she and her husband Frank Ross went to Wilder's home to confront him with her suspicions. "Marlene told you to burn my close-up", an extremely upset Arthur insisted. "She doesn't want me to look better than she does." Wilder, knowing such insecurities were common when two very different personalities were working together, tried to reassure her he was not playing favourites, although of all the actresses he directed, he admired Dietrich most of all. "The crews adored her ... She liked to find somebody with a cold, so she could make chicken soup for him. She loved to cook", Wilder recollected. Years later, Arthur called Wilder to tell him she finally had seen the film and liked it, apologised and said she would act in any future Wilder project.