So I have no license. I fly in/out of Dublin 8-9 times a year. Never had an issue.
The local field Capital paintball hosts stag do's, company outings, and there are a couple University clubs that come out to play. They may know more about licenses for their rental guns...but...I dunno.
The law is a bit like the German F stamp and the joule limit.
The Chartres thing is messing with everyone's head. The only thing I can think of, is that it's a backup site. The Barcelona thing was deemed too much of an issue due to their enforced firearm laws?
70km drive from Orly airport, which is where I'd go to, going into CDG is a nightmare, because it means it's 100km away and on the opposite side of Paris, which has some of the worst traffic I've seen.
I guess you can train it from London to Paris, then Paris down. 5 hour trip though. roughly 150 euro round trip ticket, not horrid.