The play in the play (in the play)

The key element in the film is that Juliette is playing someone who is similar to Juliette, but not herself. She’s using who she is. I’m using what she is, meaning her past and what the audience knows or imagines of her. And what happens is that it contaminates the whole film. All of the sudden you see Kristen as Kristen and you see Chloë [Grace Moretz] as Chloë.

[...] Even in the shift of perspective, because obviously Kristen is playing a character who is commenting on Kristen Stewart, but it’s a movie where you never lose consciousness of who the actresses are, and in the end that’s a very important element of the film. But that’s something I only realized gradually.  

The Dissolve: Juliette Binoche and Oliver Assayas on Clouds Of Sils Maria’s hall of mirrors, April 2015