In the end credits of the French version, Thierry Buisson was mistakenly credited as the voice of Redbeard, but the voice was actually provided by Joël Zaffarano.
Caesar and the other Romans seem to think the world is flat. In truth, they would have known it was round, since scientists from Greek culture had determined this several centuries earlier.
When Asterix and his friends leave the Native Americans,the tribe chief speaks in what is clearly Getafix's voice; he says good bye in English for one thing, which the Native Americans cannot speak.