Director Woody Allen attempted to shoot the film in Paris in 2006, but abandoned the project as it was too expensive. In this version, the lead would have been played by David Krumholtz . (As mentioned on the Knocked Up DVD extras)
This is the first Woody Allen film to go through a digital intermediate, instead of being color timed in the traditional photochemical way. According to Allen, its use here is a test to see if he likes it enough to use on his future films.
Carla Bruni, who plays the tour guide at the Rodin Museum, was also the First Lady of France at the time of filming (she has been married to then-President of France Nicholas Sarkozy since February 2008).
When Zelda Fitzgerald suggests to Gil that they leave the party and go to Bricktop's, she is referring to Chez Bricktop, the famous Paris nightclub run by Ada Bricktop Smith. Ada Smith appeared as herself in Woody Allen's Zelig as one of the modern-day "witnesses".
When casting for the movie, Woody Allen knew that he needed a french actress for Adriana so his first choice was Marion Cotillard. When Allen asked Cotillard to be a part of his movie, she was at home and talked with him for over an hour. When the conversation ended, Cotillard said: "Oh, my God, I've been talking to Woody Allen - that was Woody Allen's voice!"
For Gil's difficult and demanding fiancée, Inez, Woody Allen says he had Rachel McAdams in mind as he was writing. And when he pitched her the part, he told her, "It would be much more interesting for you to play this kind of character. You don't want to go your whole life playing these beautiful girls. You want to play some bitchy parts. It's much more interesting for you."
When Woody Allen had enough budget to shoot the movie in 2006, he contacted his preferred cast but many were working on different projects and couldn't commit. When Owen Wilson's name came up for the leading role, Allen rewrote the character to fit.
Woody Allen won a Best Original Screenplay Academy Award for this film. The Oscar was Allen's fourth and the first he had won since Hannah and Her Sisters 25 years earlier. Allen received two Oscar nominations for this movie, the other being for Best Director, they being his 22nd and 23rd nominations. Additionally, this is his first film since Hannah and Her Sisters (1986) to earn a Best Picture nomination.
Woody Allen did not attend the 2012 Oscars Ceremony to receive the Best Original Screenplay Academy Award, continuing his trend of never appearing at the event. Allen is not a member of the Academy though he did appear at the 2002 Oscars ceremony for a tribute to New York films after the September 11 bombings.
With four nominations (Best Picture, Best Director, Best Art Direction and Best Original Screenplay), this picture is the most Oscar nominated Woody Allen film since Bullets Over Broadway which got seven Oscar nominations.
The trivia items below may give away important plot points.
The movie's key art incorporates Vincent van Gogh's famous painting "Starry Night." Interestingly, the character of van Gogh does not appear in the film, though he could well have done so in the "Belle Epoque" sequence.
Probably inspired by the Moberly-Jourdain incident in 1901 in which two female academics, Charlotte Anne Moberly and Eleanor Jourdain, claimed to have experienced a timeslip into pre-revolutionary France on the grounds of Versailles.
The "Alice" who opens the door at Gertrude Stein's apartment is meant to be Alice B. Toklas, who was Stein's longtime romantic companion from September 8, 1907 (the day Toklas first arrived in Paris) until Stein's death on July 27, 1946.
Gil discovers that a woman with whom he had been dancing was Djuna Barnes, who in 1936 published her now-classic novel Nightwood. Gil's remark about Barnes wanting to lead when they danced is an oblique reference to Barnes's bisexuality and the lesbian subject matter of Nightwood. Woody Allen also named the main character of his movie Everyone Says I Love You (which was also set partly in Paris) after Djuna Barnes.