Giacomo Casanova was a real person, but most of the other characters in the movie are not. Francesca Bruni was created for the Bob Hope vehicle As Grandes Noites de Casanova (1954), in which she was played by Joan Fontaine.
Some plot elements recall William Shakespeare play The Merchant of Venice, especially Francesca Bruni's disguising as a man in order to take part in a legal council. This movie also featured Jeremy Irons and Charlie Cox who appeared in O Mercador de Veneza (2004).
When Casanova is running away from the Inquisition in the opening scene he jumps through a window and into the University of Venice. The University of Venice never existed and the building he jumps into is in fact the "Teatro Olimpico", one of the first Renaissance theaters 140 kilometers away from Venice.
The soundtrack uses an orchestra on instruments from the 18th century, staying true to the period setting of the film. It is a consortium of players from various early music ensembles in the US including the American Baroque Orchestra, Trinity Baroque, and Tafelmusik. The works are mostly derived from composers active in Venice at the time, some original music by Alexandre Desplat was used with the orchestra on original instruments.
During the short sword fight at the end of the film when they are running away Oliver Platt takes off his cape and fights with it just as Oliver Reed did as Athos in Os Três Mosqueteiros (1973). Oliver Platt played Porthos in the 1993 version of Os Três Mosqueteiros (1993).