Published by the Luxembourg Institute of Socio-Economic Research (LISER), in the "Working Paper Series" ( 2015-08), the article examines the effects of state borders on the performance of metropolitan areas in Europe. A multi-dimensional conceptualization of border effects is elaborated and empirically tested with the help of statistical modelling. The results suggest that Swiss cases and metropolitan areas recently integrated into the EU benefit the most from their border setting. When considering specific effects, a recent opening of the border as a new contact factor and significant differentiation factors have positive impacts on metropolitan functions. Alternatively, the spatial proximity of the border and its long-standing opening have negative impacts.