The German title "It Was Not the Nightingale" is a allusion to Shakespeare's Romeo and Juliet, Act 3, Scene 5:
Juliet: Wilt thou be gone? It is not yet near day. It was the nightingale, and not the lark, That pierced the fearful hollow of thine ear.[3]
Sylvia Kristel recreates the balcony scene during the visit to Verona.