The policy of the European Union, which promotes a vision of Europe without borders and has fostered the development of cooperation across borders over 25 years, has led, in some parts of Europe, to the emergence of so-called integrated cross-border regions. Thus far, the increase of cross-border flows and interactions has always been a normative and almost unquestioned policy paradigm. However, tendencies of re-bordering and signs

of growing Euroscepticism can also be observed nowadays in these border regions, which show the importance of investigating the negative externalities that can be generated by crossborder integration. This article attempts to do this by focusing on three case studies usually considered as among the most integrated ones in Europe because of cross-border flows related to work: the cross-border metropolitan regions of Basel, Geneva and

Luxembourg. Our findings show that if several decades of crossborder integration have led to the reinforcement of the functional linkages between the border regions, some effects of the cross-border integration process have also created a functional

specialisation of space that relies on social and economic inequalities. Such a situation contradicts the ideal of cross-border territorial cohesion and helps to better understand the rise of Euroscepticism in some of the border areas.