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 “phony war”. When the Germans launched their blitzkrieg invasion of France in 1940, the French Army crumbled within weeks, and with Britain retreating, an atmosphere of humiliation and defeat swept France. A new government under Marshal Philippe Pétain surrendered, and German forces occupied most of the country. A minority of the French forces escaped abroad and continued the fight under General Charles de Gaulle (the “Free French” or “Fighting French”). On the other hand, the French Resistance conducted sabotage operations inside German-occupied France. To support the invasion of Normandy of 1944, various groups increased their sabotage and guerrilla attacks; organizations