Seems like you'd want to subpoena source code or gmail history or something like that. Not much interesting in an office these days.
At this point a nuclear power like France has no issue with using covert violence to produce compliance from Musk and he must know it.
These people have proven themselves to be existential threats to French security and France will do whatever they feel is necessary to neutralize that threat.
Musk is free to ignore French rule of law if he wants to risk being involved in an airplane accident that will have rumours and conspiracies swirling around it long after he’s dead and his body is strewn all over the ocean somewhere.
The second Donald Trump threatened to invade a nation allied with France is the second anyone who works with Trump became a legitimate military target.
Like a cruel child dismembering a spider one limb at a time France and other nations around the world will meticulously destroy whatever resources people like Musk have and the influence it gives him over their countries.
If Musk displays a sufficient level of resistance to these actions the French will simply assassinate him.
PS Yes, Greenpeace is a bunch of scientifically-illiterate fools who have caused far more damage than they prevented. Doesn't matter because what France did was still clearly against the law.