Breyer was the only member of the German Pirate Party to be elected to the European Parliament, where he now sits, together with three members of the Czech Pirate Party who were elected at the same time, as one of a total of four members composing the Pirate Party in the parliament. He joined the Greens–European Free Alliance group, as Felix Reda had done in the previous legislature, and so too did the three Czech pirates. For his group, Breyer is a member of the European Parliament Committee on Civil Liberties, Justice and Home Affairs and an alternate member of the European Parliament Committee on Legal Affairs.
