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
Overseas country of France Caledonia, which has the unique status of a "sui generis" collectivity, is also sometimes incorrectly referred to as an overseas country. However, if the people of New Caledonia choose to remain part of France in a referendum on independence scheduled for November 2018, the community may become an overseas country. Overseas country of France Overseas country () is the designation for the overseas collectivity of French Polynesia. French Polynesia was an overseas territory until the constitutional reform on 28 March 2003 created the overseas collectivities. Then, on 27 February 2004 a law was passed giving French Polynesia the particular designation