GRECO is the anti-corruption body of the Council of Europe, not to be confused with the European Council or the Council of the European Union. It is an independent organization, founded in 1949. The Netherlands was one of the founders. There are now 47 European countries members, more than the European Union.
The Council, based in Strasbourg, is the guardian of democracy, the rule of law and human rights, but cannot impose sanctions. The organization does have jurisdiction: for example, the Council can sue parties before the European Court of Human Rights.