Rules of the Eurovision Song Contest

A detailed set of rules and obligations, which all participating broadcasters and participants in the annual Eurovision Song Contest (French: Concours Eurovision de la chanson) must uphold, is produced annually ahead of each edition of the international song contest. These rules are drafted by the contest organisers, the European Broadcasting Union (EBU), and approved by the contest's reference group.

Source: Wikipedia — Rules of the Eurovision Song Contest (CC BY-SA 4.0)