Wonderful!

I also consider this film to be truly beautiful. But I disagree with your theory that it would be concerned with enlightenment, or that it would even consider it possible. Of course, this is only my interpretation, since I haven't watched Breillat's interview, so I have no idea what she says about the film.

I do not know French very well, so I watched it with English subtitles, and I've found that at certain rather important moments, the translation missed some of the meanings that could be inferred from the original text.

I've transcribed, as best as I could, a passage from the dialogue between the two main characters in the scene where the woman proposes the deal to the man:

Her: "Je vous payerez." ("I will pay you.")
Him: "Que espérez vous?" (the English subtitle, reading as "To what end?", misses altogether what could be interpreted as a reference to Immanuel Kant: a more sound translation would be "What would you hope for?" (in the sense of "What do you hope to get out of it?") - where the same question was considered by Kant to be one of the most fundamental questions concerning the human condition, formulated as "What may one hope for?". Of course, Kant being a philosopher of the Enlightenment, the question concerning the limits of human knowledge was equally important for him. But the question about what may be hoped for is not concerned with theory, or in Kantian terms, with theoretical reason (and hence with understanding or knowledge), but with that which limits our possibilities of action, with freedom - it opens the domain of practical reason, hence ethics and politics - the domain of "What should I do?". All this is linked with the problematic translation of her immediate next reply.)
Her: "Savoir." (the English subtitle read as “To find out.” - I'll come back to this point.) "Parce-que vous, qui n’aimez pas les femmes, vous pouvais justement me regarder... Je veux dire, avec de l’impartialite." ("Because you, who have no love for women, may justly regard me... I wanted to say, with impartiality.")

The psychoanalyst Jacques Lacan explained that, in French, there are two words, savoir and connaissance, that denote distinct types of understanding. Connaissance could be more aptly translated as knowledge, something obtained through the construction and testing of theories. The ancient Greek philosophers named this episteme. On the other hand, savoir, as in the compound expression "savoir-faire" (know-how) is a practical, maybe even intuitive type of knowledge. It is possibly something similar to what the Ancient Greeks called techne - in which sense we speak even today of the technique of a certain master artist, as something extremely difficult to imitate. While an episteme could be learned in school, by studying theoretical textbooks, a techne is a lived knowledge, that may be eventually learned from another only through direct contact with that person. To learn the art of statecraft one had to frequent great political leaders, etc.

The woman has just tried to commit suicide. The man stopped her. After her wound was tied, she gave him a fellatio, and the dialogue I've quoted above followed. He asked her what does she hope for, that she is offering him payment, and she answered "savoir". I believe it is a kind of know-how that she was seeking, of how to cope with suffering, with her life. The title of the film is "Anatomy of Hell".

In the case of this film, there were two separate hells. Hers in the foreground, his in the background (there was that scene where he explained why many men tend to drink - to fill the lack of genuine inter-subjective communication - and that even in the intimacy of the bedroom one's thoughts cannot reach the partner's being - that everyone is essentially alone).

The reference to his alleged impartiality I consider to be misleading. At the beginning he was definitely anything but impartial. Having no love for women, he was not neutral towards them. He positively loathed them. It was not his impartiality that appealed to her, but his otherness, his being a complete stranger to women. In the sense of the Hegelian dialectic of the struggle for recognition, she needed to be recognized as what she is in her essence, beyond the accepted conventions of morality, beyond the socially imposed hypocrisy, and for that she needed someone who is different from her, the more distant, the better.

Was her project ultimately successful? For her, I do not know. She disappeared. And if he was to a certain extent enlightened by their encounter, it was a kind of Faustian Enlightenment, one illuminated by the fires of hell, and he, one of the damned within.