Not sure if this will help. I will keep looking for more info that might be a little more simplistic. Unless you know more about France then I do maybe it will make perfect sense to you. It seems like there might be a difference.
Metropolitan France refers to the part of France in Europe, including Corsica, as opposed to the overseas departments and overseas territories, which, while integral parts of the French Republic, are regarded as Overseas France. In the overseas departments, a person from Metropolitan France is often called a métro, short for métropolitain.
As of January 1, 2006, there were 61,044,700 people living in Metropolitan France, while there were 2,543,000 people living in Overseas France, giving a total of 63,587,700 inhabitants in the French Republic.
Metropolitan France excluding the island of Corsica is referred to as Continental France (la France continentale), or just the Continent (le continent). In Corsica, people from Continental France are referred to as "Continentals" (les continentaux).
info came from here
From other stuff I read It sounds like there is a distinction in government and
geography between the two. It is part of France but somehow has a distinction that makes it "metropolitan france" differentiating it from just being in the country of France. I don't think it means metropolitan as we think of it as equivalent to the city. I hope that helps but I am not sure it will...