The characters, Jessica and Gwen, played by Megan Campanile and Aleen Artinian, were named after the Producer and Production Designer of Folie à Deux. Whenever any of the two names were called, it would cause confusion on set.
C.S. Lewis (Clive Staples Lewis), author of the Narnia series, was the inspiration behind naming the protagonist Clive Hasurdy. And to continue the French theme of the film, Hasurdy comes from the French word "hasard", meaning chance or risk.
After an actor's cancellation the night prior to filming, Yvonne Schneider (art director), was chosen to play the role of Lucy Higguns, the women's rights activist, due to her intense research of the 1920s and that particular subject.
The character name, Holly Charmant, was motivated by Audrey Hepburn's character name, Holly Golightly, from "Breakfast at Tiffanys". The film was also a form of inspiration in regards to story and the relationship between Cara and Clive.
The cookie in the opening sequence was actually smothered in strawberry yogurt.