"L'amour est un oiseau rebelle" was an aria from Carmen which was once played in the Parliament of the Daleks. The Dalek legislature heard it because it was being transmitted from the core of the Dalek Asylum from a mysterious source — one that was later revealed to be the Dalek created from Oswin Oswald. The Eleventh Doctor said he had played the triangle in the recording heard, but that he was "buried in the mix". (TV: Asylum of the Daleks)
Behind the scenes
Although the piece is never named in Asylum, it's definitively said to come from Carmen, and is one of the most recognisable arias in the world.