The building of the Berlin Wall had begun in the night of August 13, 1961, right through the set at the Brandenburger Tor. The team, discovering the change in the morning, had to move to Munich to shoot the missing scenes on the parking lot of the Bavaria Film Studios, where a copy of the lower half of the Brandenburger Tor had to be built.
In James Cagney's autobiography, he says that Horst Buchholz was the only actor he really hated working with because he was uncooperative and tried all kinds of scene-stealing moves, which Cagney depended on Billy Wilder to correct. Had Wilder not firmly directed Buchholz, Cagney said that he "was going to knock Buchholz on his ass, which at several points I would have been very happy to do".
Pamela Tiffin was reportedly having trouble acting with such experienced performers. Legend has it that James Cagney helped her by giving her the famous advice about acting: "Walk into a room. Plant yourself. Look the other fella in the eye and tell the truth."
When Billy Wilder was at Paramount, he often clashed with an executive at the studio named Y. Frank Freeman. Freeman was from Georgia and would often brag about his extensive holdings of Coca-Cola stock. That relationship was part of the inspiration for this project.
In addition to the "Yes, We Have No Bananas" song, Billy Wilder also borrowed the climactic switcheroo from Sabrina (1954) right down to the hat and umbrella. Piffl goes to London instead of MacNamara, just as Linus Larrabee goes to Paris instead of David Larrabee.
Joan Crawford (then on the board of PepsiCo) telephoned director Billy Wilder to protest the movie's Coca-Cola connection. Wilder then added a final scene in which James Cagney buys four bottles of Coke from a vending machine. The last bottle out of the machine isn't Coke - but another brand... of Pepsi.
The instruction at the front of Billy Wilder and I.A.L. Diamond's screenplay reads: "This piece must be played molto furioso". Suggested speed: 110 miles an hour - on the curves - 140 miles an hour in the straightways. "
At one point Cagney says, "I wish I were in hell with my back broken," a line Billy Wilder used in at least two of his earlier films. Humphrey Bogart says the same line in "Sabrina", and Akim Tamiroff says a slight variation, "I wish I were in a black pit with my back broken," in "Five Graves to Cairo". Ray Walston later repeats the sentiment in "Kiss Me, Stupid."
To cause problems for Otto Piffl (Horst Buchholz), James Cagney gives him a cuckoo clock that plays the old English song,"Yankee Doodle," causing Buchholz to get arrested by the East Germany police. Jimmy Cagney played the lead role in Yankee Doodle Dandy (1942), the story of George M. Cohan, the composer of "Yankee Doodle Dandy."
While watching "the blonde lady" dance at The Hotel Potemkin", one of the Russians takes off his shoe and bangs on the table with it. The banging eventually causes the photograph of Nikita Khrushchev the fall out of its frame to reveal the picture of Josef Stalin, his predecessor, behind it. Khrushchev, who is mentioned several times in the movie, is supposed to have taken his shoe off and banged on the table with it at the United Nations.
In an early scene, MacNamara begins negotiating with the three Russians, who offer him a Cuban cigar. The Russians tell MacNamara that they have a trade agreement: "We send them rockets, they send us cigars." What was written as a joke later turned out to be the truth - within one year (October 1962), Russian missiles were discovered in Cuba.
When Cagney tells Otto he must give the couple a wedding present Scarlett claims that Otto's friends did not give them any gifts but instead sent the money to unemployed cotton pickers of Mississippi. Cagney was accused of being a communist sympathizer for sending money to striking cotton workers in the 1930's.
When trying to return to West Berlin the car Cagney is in is being chased by another car. Cagney asks his driver what kind of car it is. The driver tells him it's a 1937 Nash. The 1937 Nash was the car of choice in late 30s and early 40s gangster films.