I routinely watch this movie about once a year, and GD held my interest--huge fan of his--in earlier viewings, but Fabrice Luchini each time I see his work in this film, it gets better and better to my eyes, what an actor. Stunning.
I agree! He was perfectly cast and does an amazing job. I thought the whole movie was quite good, and obviously the other lead actors are enormously talented, but I found myself growing impatient during the scenes without Derville and looking forward to his reappearance. Luchini more than does justice to this intriguing character.
Amazing, indeed! I recently smuggled in a copy of "La Discrete" on VHS. It's just on VHS like this movie. Loads of Luchini. Front and center. It's a great role for him; like this one was: very cerebral. Fantastic!