Chances are that C. must leave France.
He loves his job (he’s one of the few in Europe who can do it), the company he’s consulting for just loves him, but the French government doesn’t give a shit about his Dutch work permit, and the fact that he’s hired full time by a Dutch company. “As long as he’s American, he’s not even getting around the building”.
Now. US immigration policies are the biggest evidence of clueless dumbassness of law makers in Washington (you can’t pretend the world ends beyond Mexico, dudes), but at least they seem to be democratic in their jerkness: you may come from Lesotho or from Australia, it’s the very same thing.
In France are they making it personal?? Because, AFAIK, with a work permit issued by a EU country you can work, like, in every EU country!
I’m really furious. Not only because this hurt someone I love, but also because democracies evidently aren’t working anymore, if they can so easily deprive us of the very right to be happy where we want to be. There’s something deeply flawed in it.