This paper deals with the process of creating the European Coal and Steel Community (ECSC), the first long-term functional organization made of European states, from which the EU was born. Although previous attempts of European integration were unsuccessful, they contributed to the development of the European idea, as well as the first attempts of post-war integration, which became more and more intense due to post-war and Cold War circumstances. However, the impossibility of connecting on a supranational basis and poor German-French relations undermined cooperation. France based its post-war security and economic development on limiting the German steel industry and on use of its (Ruhr) coal (resources crucial to warfare and industrial development). Since the USA and the UK due to the Cold War circumstances wanted a strong Germany within the Western bloc, they will undermine French plans by insisting on abolition of every control that was put upon Germany afer War. Therefore, France will have to find a new solution acceptable to the USA and Germany, and it will found it in Monnet's memorandum to Schuman and in the Schuman Declaration that followed, which proposed the unification of the coal and steel sectors, which will enable the final rapprochement of these two countries and invite other European countries to participate in newly established European organization. After the negotiations, six European countries will sign the Paris Agreement, in which, based on the Schuman Declaration, they will accept the creation of a supranational community to which they will cede part of their sovereignty and thus enable long-term cooperation built on mutual trust.