The "Hexagon" is also rather at odds with how France perceives itself culturally. If you had to break France up into broad regions, you'd have Paris, the North, the West, the East, the Southwest, and the Southeast. That's a center with five corners. When one talks about "the South of France", it's never an additional region between the Southeast and the Southwest, it's always meant as either or both. There is no "Southern region" of France. There's water where a hypothetical sixth angle should be.
1. Brittany is "a" Northwestern region, it isn't "the" Northwestern region.
2. Marseilles and Lyons are "sometimes" considered the 2nd and 3rd largest cities? Really? As far as I know they are always considered the 2nd and 3rd largest cities. What's the competition?
It depends on the way you count their population. If you go by city proper, then Marseille is second and Lyon is third. If you go by urban area/metro area (which makes more sense in my opinion), then Lyon is bigger than Marseille.
I think that 2nd "i" is not only fluous, it's SUPERfluous.
2. Marseilles and Lyons are "sometimes" considered the 2nd and 3rd largest cities? Really? As far as I know they are always considered the 2nd and 3rd largest cities. What's the competition?