The new seat of l’Eurodistrict Regio Pamina association is located in Lauterbourg, on the French-German border, north of Strasbourg.This trans-border intitution has been created by the german Länder of South Palatinat and Mittlere Oberrhein and north of the french region Elsass . The renovation and extension of the former customs offices in Lauterbourg will symbolise this French-German initiative. Our project is organised along a longitudinal axis: a south-north corridor, which symbolically links France to Germany through the building. A bio-climatic system providing a large amount of the energetic needs of the building is also organised along the corridor. It stretches outsides as a bio-climatic pipe, links the heat exchange system.The west façade of the extension is covered by a vegetal filter, protecting the offices from the nearby road and sun exposure. The conference room emerges from this vegetal curtain. It is designed as an intriguing volume of wood and glass, radiating light while occupied and showing the activity of the building.