Benelux Economic Union (bĕn`əlŭks'), economic treaty among Belgium, the Netherlands, and Luxembourg. It arose out of a customs convention signed in 1944, but was not fully established until 1958. The union was established to promote free movement of workers, capital, goods, and services in the Benelux region. All three countries were also founding members of what has become the European Union European Community (EC), an economic and political confederation of European nations, and other organizations (with the same member nations) that are responsible for a common foreign and security policy and for cooperation on justice and home affairs.
..... Click the link for more information. (EU), which has implemented these same reforms. Benelux was the first entirely free international labor market, but its goal of merging the fiscal and monetary systems of the three countries was only largely fulfilled when most EU nations replaced their currencies with the euro (2002).

Benelux Economic Union

Economic union of Belgium, the Netherlands, and Luxembourg. The three countries formed a customs union in 1948, and in 1958 they signed the Treaty of the Benelux Economic Union, which became operative in 1960. Benelux became the first completely free international labor market and contributed to the establishment of the European Economic Community.