You are right. Metropolitan area makes more sense. There are administrative reasons for a metropolitan area to be subdivided in cities or towns but effectively

You are right. Metropolitan area makes more sense. There are administrative reasons for a metropolitan area to be subdivided in cities or towns but effectively it acts as just one city. I was thinking about Paris (city 2 million, metro 12.5 million) or Barcelona (city 1.6 million, metro 5.5 million). Similar to your example.