The EU and the OIF have both developed to become international organisations that combine economic, geopolitical and cultural-linguistic policies. This article deals with the fascinating interface of such policies. The main focus resides on the discourse by which both organisations construct their linguistic and cultural diversity concept and on how they deal with language rights. The role of other divides in the debate on linguistic and cultural diversity in international cooperation is investigated. Furthermore, the analysis includes future scenarios and integrates the frequently used arguments in on-going Belgian public debates on French as an international language and in European debates on French as the legal language for the EU.