Not necessarily. We're looking at the second-most taught foreign language, so it could be something like:
Dutch areas: Dutch as first language, French as most common foreign language, English second
French areas: French as first language, English as most common foreign language, Dutch second
German areas: German as first language, French as most common foreign language, Dutch second
This would result in the map above even though all three are different once you look at them. I have no idea if it's actually true of course, just saying that it's possible