It's called 'Berceuse', which is French for 'lullaby'. It's from an opera by Benjamin Godard called Jocelyn. I have zero idea what the plot is, but it's from an epic poem. Maybe Superfrenchie knows. Everybody likes this song best, though. It's really restful and won't wake the kitty.
Click here for the video, or watch the embedded version in your Pliny-skin page.