On 20 June 1950, in Paris, representatives of the Six began negotiations on the Schuman Plan. Open to the idea of an independent High Authority, the Benelux countries called in return for an intergovernmental body, the Special Council of Ministers, to be set up. A Common Assembly was established.

There were also plans to set up a Court of Justice to settle disputes. In economic terms, the negotiators endeavoured to give the Community the means to break up the cartels controlling German heavy industry and to organise mining and steel production. The treaty establishing the ECSC was initialled by the six delegations on 19 March 1951.