Christian Clavier, who provides the voice for Asterix in this movie, portrayed him in the first two Asterix live-action-movies, Asterix and Obelix vs. Caesar (1999) and Asterix & Obelix: Mission Cleopatra (2002). He took over from Roger Carel who had voiced the character since Asterix the Gaul (1967).
The Roman-sympathizing Gaul leader (Ceramix in English, Aplusbégalix in French, Elpiubelgalix in Italian) briefly met by the protagonists was the main antagonist of the 1966 comic book "Le Combat des Chefs" (Asterix and the Big Fight).
There is a recurring joke about Druids being forbidden to write notes. This is actually historically accurate, as the Druids' knowledge was considered too sacred to be written down and was transmitted orally.
After The Twelve Tasks of Asterix (1976) this is the second animated Asterix movie that is based on the original characters by Albert Uderzo and René Goscinny but not on a specific Asterix volume.
The screenplay is not adapted from an already existing comic book.