It is revealed that "Casino Royale", the first James Bond novel, is what inspired Castle to pursue writing as a career. Though not technically a Bond girl, Stana Katic has a small role in Quantum of Solace (2008), the first sequel to Casino Royale (2006).
The characters with the last name El-Masri are Egyptian. "Masri" literally means "Egyptian" in Arabic.
The American embassy shown in the episode is the Paris Stock market. We can see Bourse on the top of the building
In 2013, Molly C. Quinn played Superman's cousin Kara/Supergirl in the animated movie Superman: Unbound (2013). Christopher Heyerdahl, who plays the man whom Castle recruits to find Alexis, played Kara's father Zor-El in the Smallville (2001) episode "Lara (2007)".