Or they just connect to a mothership with keys on the machine. The authorities can have the keys, but alas, they're useless now, because there is some employee watching the surveillance cameras in the US, and he pressed a red button revoking all of them. What part of this is illegal?

Obviously, the government can just threaten to fine you any amount, close operations or whatever, but your company can just decide to stop operating there, like Google after Russia imposed an absurd fine.

You know police are not all technically clueless, I hope. The French have plenty of experience dealing with terrorism, cybercrime, and other modern problems as well as the more historical experience of being conquered and occupied, I don't think it's beyond them to game out scenarios like this and preempt such measures.

As France discovered the hard way in WW2, you can put all sorts of rock-solid security around the front door only to be surprised when your opponent comes in by window.