Better yet - give them free tickets and weapons. Tell 'em to have a good time. But take their passports and make sure they don't return to France.
Yes I encourage all European Muslims to do the same, and gather in one place.
Problems solved.
In that case, they ought to give them used French military weapons. In good condition, never fired and only dropped once.
On the money. Don’t stop these rabid pharisees from going. Going solves two problems. It gets the rabid pharisees out of the West. And in the nirvana they want to go to they can wind up dead. These types get offended by bikinis but will happily watch and participate in beheadings, stonings etc. Its little wonder Jesus devoted more words to show his contempt for rabid pharisee types than any other group.