144 11.4 Summary The Saar-Lor-Lux-region shows a large variety of transfrontier co-operation activities. The part- nership of several institutions including parliaments, governments, chambers and associations and the co-operation of regional authorities, have produced various spatial definitions of this „artificial“ area. This confusion about its demarcation and its size creates problems for the population concerned to ac- cept this regionalization as a necessary development and to identify themselves with the region. At the same time on a local level several sub-regions within Saar-Lor-Lux are established. Here local authori- ties try to improve, and increasingly to institutionalize, their border crossing contacts. The present work follows the question how much these cross border co-operations contribute to the european integration process compared with the authorities mentioned above. It is based on the model of city-networking, which is gaining increasing importance in the european development discussion. Its applicability to cross border matters is portrayed within three examples. With the Agglomération Transfrontalière du Pôle Européen de Développement Longwy-Rodange-Athus (PED), the Europä- isches Tal der Obermosel and the Saar-Rosselle-Raum three areas within Saar-Lor-Lux were chosen where local authorities already achieved a relatively strong institutionalization of their cross border co- operation. The co-operation within these areas started a very dynamic development process, which has been advanced considerably by the financial support of the community initiative INTERREG II and by amendments in national and international law. A descriptive analysis of the activities within these spaces forms the basis of a following examination of the advantages and impediments to the co-operation. The latter were established by a survey with local protagonists. This survey reveals totally different basic conditions for the cross border co- operation, which depends very much on the existing institutionalization. Another determining factor is also the professional support of political activities, as guaranteed for the PED by the Observatoire de l’Urbanisme in Longwy and for the Saar-Roselle region by the Kooperationsbüro at the Stadtverband Saarbrücken. They show structures, which promise a certain continuity of the co-operation in spite of possible changes of the politicians. This development also produces a thematic diversification of co- operation. ‘Tough’ subjects like urban development, environmental protection or the common operation of institutions increasingly become part of transfrontier co-operation of local authorities. In spite of structural, legal and administrative hindrance most of the involved authorities within zones close to the border, profit from a common language or cultural background. Additionally the transfrontier activities meet with general acceptance of the population, because the results influence their life in a positive way (e.g. improvement of cross border public transport). Form and content of local transfrontier co-operation very often show typical phenomena of city- networking: its voluntary nature, complementary partners as well as the creation of unconventional insti- tutions, which totally differ from national administration hierarchy, show their motivation to gain more importance on the regional, national and even international level by the use of synergy effects. In the present case this also contributes to overcome the EU internal borders which define those territories as the core areas of the european integration process.They are examples for a bottom-up development, which stabilizes the cohesion of Europe and improves the mutual understanding of the population within the border areas.