Given that the alleged incident may or may not have occurred in the "People's" republic, it can (possibly) only be dealt with there. If the Chinese authorities wish to act upon any event that may or may not have occurred, then they can go about issuing warrants etc.
But I suspect they won't (or maybe they will).
Any other action, as Keith has pointed out, is going to be Civil. In every legal system I can think of, civil action requires a lower level of proof, but proving the event may rely on witnesses, who may be a long way away, CCTV, which will be in China, other details that may be expensive or impossible to get. Mind you I suppose if the lawyer thinks his client's got enough money, he's got a case!
No doubt Bernie's got himself involved somehow. Frankly, I suspect it might only shorten Sutil's career by a few months anyway.
Note the language of "remaining fully committed" etc. Usually the last thing said before somebody is given the punt, though usually in respect of performance. Oh wait......