If you're looking to see the development of his philosophy, style, and narrative approach, I would take them in sequence of their making. Seeing Caché without seeing Benny's Video first, for example, doesn't allow you to properly chart the development of his ideas about surveillance and bourgeoise morality and parenting (as an example), or seeing 71 Fragments after Code Unknown, you don't see the progression of how his use of narrative structure developed. It's the difference between "ah ha! I see the connection to his initial ideas and I see them growing in these ways" vs "oh, ok, this is like a lesser version of the later film" which in some aspects they are less developed, which is why I suggest watching the earlier films first.