The report presents the final results of a targeted analysis conducted within the framework of the ESPON Programme and the METROBORDER project. This document demonstrates the potential and the development of cross-border polycentric metropolitan regions in Europe. It focuses on the study of two border regions: the Greater Région and the Upper Rhine. The analysis focused on their external positioning, their internal organisation and their institutional and functional dimensions. Identified as "emerging and promising spatial configurations in Europe", the cross-border polycentric metropolitan regions were defined according to criteria of polycentricity, metropolitan quality, functional and institutional integration and governance.