Institutional seats of the European Union are based in Luxembourg City along with the European Investment Bank. The Economic and Social Committee and the Committee of the Regions are entirely based in Brussels while the European Central Bank is based in Frankfurt and Europol is the only agency to have its seat fixed by the treaties, in The Hague. Separately, the Treaty of Nice establishes Brussels as the venue for all formal summits of the European Council after 2004. However some extraordinary sessions are sometimes held outside the city. The European Council's seat is however fixed by a declaration rather than a protocol, meaning it is
Member of the European Parliament Member States to the Union. The EU's annual budget is adopted jointly by Parliament and the Council of the European Union, within overall limit on EU spending decided on by unanimous agreement of all Member States and a multilateral Financial Framework laid down by Council with Parliament's consent. The Parliament may also block certain Commission decisions where there has been a delegation of powers to the Commission and may repeal such delegation of powers. The Parliament also elects the European Ombudsman and holds hearings with candidates for the President and Board members of European Central Bank, the Court of Auditors