All I would add to the previous comments is that Rohmer's films are subtle ... almost too subtle. You can watch them and think "nothing's happening here", then, over time, they come back into your mind with new insights and for me anyway, I want to watch them again. The thing about this film is that Claire is almost completely silent, unlike her younger sister, so we get no sense of her personality at all. The question is, "How much does she manipulate what happens?" For example, the final scene happens because she asks Jerome to take her across the lake even though she knows her boyfriend is not there and it is clear there is a storm coming. Did she do this to be alone with him? She did it before at the volleyball game, deliberately injuring herself (at least, that is what her boyfriend implies when he is perplexed that she hits the ball in exactly the way he told her not to). This requires her to sit, surprise, surprise, with Jerome and have her sore finger massaged by him. See - -it's subtle. Watch it again and see that Claire's apparent passivity and silence is actually extremely manipulative. That's what makes Rohmer's films so emotionally complex and interesting. They go beyond simplistic good character/bad character dichotomies as in most movies.
Review of Claire's Knee
