The areas in orange are closer to France, than a point in France is to itself.
Some of this sounds really wrong, but you can verify it all on Google Earth!
Some examples:
Paris is closer to London (325Km) than Lyon (395Km)
Marseille is closer to some places in the Algerian and Tunisian Sahara than Calais.
Calais, in turn is closer to the southern tip of Norway than the Cote D'Azur.