Union outline the locations of the following institutions: The European Parliament has its seat in Strasbourg, hosting twelve monthly plenary sessions (including budget session). Brussels hosts additional sessions and committees (including being used in September 2008 for normal sittings when the Strasbourg chamber was damaged). Luxembourg City hosts the Secretariat of the European Parliament. The Council of the European Union has its seat in Brussels, except during April, June, and October, when meetings are held in Luxembourg City. The European Commission also has its seat in Brussels, although some departments and services are hosted by Luxembourg City. The Court of Justice of the European Union, (along with its component courts, the European Court of Justice and the General Court), the Court of Auditors and the European Investment Bank are based in Luxembourg City. 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 less binding than the other seats. The 2011 Treaty Establishing the European Stability Mechanism (ESM) states that the seat of the ESM must be in Luxembourg. The ESM should be ratified and active in mid-2013 and it is allowed to establish a liaison office in Brussels. Non-fixed seats There are numerous other bodies and agencies that have not had their seats fixed by treaties. Brussels hosts the European Defence Agency (as NATO and formerly the WEU are also in the city). Luxembourg City hosts the Translation Centre for the Bodies of the European Union and the European Investment Bank. Strasbourg and Brussels both host the offices of the European Ombudsman. The other agencies are spread across Europe and since the 2004 enlargement, there has been a drive to locate more agencies in the new member-states to make a more equal distribution. However, some problems have been encountered with basing agencies in the eastern states. For example, Frontex, the new border agency, has had problems recruiting skilled experts because many do not want to live in the agency's host