Fairly early in the movie (around 18:00), Michèle (main character) drives her car to the restaurant where she's meeting others for dinner. She deliberately and repeatedly rams the back of her car into the front of Richard's (her ex) car, causing some damage.
She then enters the restaurant, greets Richard as if nothing had happened, and proceeds to have a lovely dinner (which includes casually telling her dinner companions that she had recently been raped).
Later on they come out of the restaurant and after a brief parting conversation about some business matters near their cars, she points out to Richard that "Somebody trashed your fender." Richard responds incredulously, "Somebody!?", indicating (at least to me) that he clearly knows she did it.
Why did Michèle damage Richard's car?
Why wasn't Richard more furious? (As one would be after someone just deliberately damaged your car.)
Obviously this movie as a whole was filled with characters with bizarre and complicated motivations (which I still do not quite understand), but I was hoping I could at least understand this little detail here.