The Universal Declaration of Human Rights, article 11, states: "Everyone charged with a penal offence has the right to be presumed innocent until proved guilty according to law in a public trial at which he has had all the guarantees necessary for his defence.".
The Convention for the Protection of Human Rights and Fundamental Freedoms of the Council of Europe says (art. 6.2): "Everyone charged with a criminal offence shall be presumed innocent until proved guilty according to law".