Belgium–Luxembourg Economic Union

BLEU was created by a treaty, signed on 25 July 1921, despite a referendum against such a proposal, between Belgium and Luxembourg, and came into effect upon ratification by the Luxembourg Chamber of Deputies on 22 December 1922.

[1][2] Under the terms of the treaty, the economic frontier was lifted and the Belgian franc and Luxembourg franc were set at a fixed parity (though revised in 1935 and 1944) establishing a fixed exchange rate system, which existed until the introduction of the euro.

[3] It has been seen as the forerunner of the Benelux Union, which was established as the Benelux Customs Union in 1944 by the London Customs Convention and also includes the Netherlands.

International trade statistics were available for BLEU only as a combined entity until 1999 when European Community rules required split information.

Belgium was only allowed to alter its customs tariffs or conclude trade treaties after consultation with the Luxembourgish government, whereas before 1918 Luxembourg had to go along with German decisions.