Any citizen of the Union and any natural or legal person residing or having its registered office in a Member State has the right to refer to the European Ombudsman cases of maladministration in the activities of the institutions, bodies, offices or agencies of the Union, with the exception of the Court of Justice of the European Union acting in its judicial role.

http://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:12012P/TXT&from=EN