On 28 August 1944, the Belgian Foreign Ministry issues a note on the draft Franco-Belgian economic agreement concerning the establishment of a limited organisation for European economic cooperation between Belgium, France, Luxembourg and the Netherlands.
Le 19 janvier 1945, Jules Guillaume, ambassadeur de Belgique à Paris transmet une lettre à Paul-Henri Spaak, ministre belge des Affaires étrangères, dans laquelle il évoque la position de la France quant à la création d'une union douanière entre la Belgique, la France, le Luxembourg et les Pays-Bas.
On 23 February 1945, Belgium and France conclude limited economic agreements on the resumption of trade, the exchange of tax information and payment facilities between their two national banks.