The Democratic Republic of the Congo (formerly called Zaire and the Belgian Congo - during the colonial period) speaks French because it was colonized by the Belgians. Since the official languages of Belgium are Flemish and French, it makes sense that the administration of the Belgian Congo would have been in either French or Flemish. The reason why French was chosen and not Flemish was for several reasons. Firstly, French was the more populous language in Belgium. Secondly, it was the dominant language among the leadership and aristocracy in Brussels (the capital of Belgium). Finally, as there were numerous French colonies in Africa, but no other Dutch/Flemish colonies, French also served as an international language for African governance.