Had Chabrol seen 'The Unsuspected' (1947)?
A couple of days ago, I saw Michael Curtiz' stylish thriller again after many years. And I found quite a number of plot layout details similar to Chabrol's "Masques", as e.g. the leading character is a frontman in broadcast entertainment, the mouldings of Rains' and Noiret's characters are almost alike, including the deliberately chosen ominous Names: Victor Grandison (which rings like grandeur, grandseigneur...) - Christian Legagneur ("gagneur" means "winner"); the young woman ward, the "intruding" and investigating young man (both under, more or less, "false" identity), the illustrious side characters, the scrap yard scene, and, last but not least, the final scene with the murderer being cornered "on air", including his "last address" to the live audience.
All these, and more, similarities cannot possibly be purely coincidental!
But none of the reviews of "Masques" that I have read so far would mention "The Unsuspected" as a highly likely source of inspiration for Chabrol layout of his thriller. It would be interesting to hear Mr. Chabrol himself on this.