Twitter doesn't encrypt messages, so there is indeed no chance of that happening - after all the reasoning for this arrest is fundamentally inapplicable to Twitter.

It's however a very very very slippery slope to prosecute someone for providing the tools to hold encrypted communication, just because this is also used by criminals. A lot of privacy oriented services would probably have to exit France if this holds up

I don’t know in France, but at least in Italy companies are not a shield for penal responsibility; crimes are always committed by persons. If a company does something criminal, someone is responsible for that decision within the company, and that could be the CEO.

CEOs can be liable for intentional or grossly negligent non-compliance, among other things.

Elon Mustk is a very important person; Tesla, SpaceX, Starlink, Twitter. He provides services to the military with the Starlink and he is deeply connected to the state with SpaceX.

On the other hand Pavel Durov is "homeless". He is like a normal citizen.

If a court orders twitter to take down a tweet, and twitter doesn't comply, then I believe anybody that is responsible for that inaction, including Elon if he was aware and didn't act may be tried