France–Germany relations of the further integration of the EU. They are sometimes described as the "twin engine" or "core countries" pushing for moves. A tram straddling the Franco-German border, across the river Rhine from Strasbourg to Kehl, was inaugurated on the 28th of April 2017 symbolising the strength of relation between the two countries. Both France and Germany track their history back to the time of Charlemagne, whose vast empire included most of the area of both modern-day France and Germany – as well as the Netherlands, Belgium, Luxembourg, Switzerland, Austria, Slovenia, and northern Italy. The death of Charlemagne's son Louis the
France–Germany relations regain Alsace-Lorraine and briefly resume its old position as the leading land power on the European continent. France was the leading proponent of harsh peace terms against Germany at the Paris Peace Conference. Since the war had been fought on French soil, it had destroyed much of French infrastructure and industry, and France had suffered the highest number of casualties proportionate to population. Much French opinion wanted the Rhineland, the section of Germany adjoining France and the old focus of French ambition, to be detached from Germany as an independent country; in the end they settled for a promise that