I've been looking at Ryanair's operations around Paris and am puzzled as to FR's network choices. I realise CDG and Orly have high-ish fees and FR have chosen to use Beauvais as a proxy base while not incurring French social employment costs.
I see that FR also fly to Vatry, a very long way east of Paris - not far from Reims. The destinations at Vatry are also flown from Beauvais. Unlike Beauvais with bus services locally andto Paris, Vatry is about 25 km from the nearest train station and is not served by a bus service at all.
So why do FR fly to Vatry at all ? Is it driven entirely by migrant agricultural workers or is there some other story going on ? Vatry is a cargo airport - seems unlikely that Beauvais management will worry too much about threats by FR to up sticks and move to Vatry...
You need to look at it differently and not limit it to Paris area.
It's mainly because of cultural connections as Portuguese are the largest single European group living in France while Moroccan is the second largest African group living in France. Combined both make up 2.7-3 million people.
Will explain how such regional airports in France have links to Portugal and Morocco.
What was more random is FR started off in Vatry with Oslo and Stockholm if I am not mistaking.