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
Seat of the European Parliament in Strasbourg official home. The Parliament's five buildings, all named after distinguished European politicians, are located in the "Quartier Européen" (European Quarter) of the city, which it shares with other European organisations which are separate from the European Union's. Previously the Parliament used to share the same assembly room as the Council of Europe. Today, the principal building is the Louise Weiss building, inaugurated in 1999. The Louise Weiss building (IPE 4) (named after Louise Weiss, a French former member of the parliament), is located in the Wacken district of Strasbourg, south of Schiltigheim, between the 1920s workers' suburban colony ("Cité ouvrière")