well to be fair this was initially about Arnold Moss as Fouché specifically so
set aside the fact that he has the best role in The Black Book, his Fouché draws from real Fouché’s own personality in terms of sense of humor and talkativeness. i think Fouché has this image of a sinister and cunning statesman, which he was in a way, but he was more known to be a chatterbox and a jokester. talking a lot made it easier to lie, as per his own admission
one thing i can criticize in his characterization (and in the script) is his penchant for violence. the Lyon massacres cling to his reputation (as they should) but as hard to believe as it may be, Fouché wasn’t inherently violent and always preferred to avoid bloodshed if possible
but his character is perfect as it is in this movie!
If I may jump into the conversation: one of the reasons I love “The Black Book” Fouché (apart from being an amazingly fun and enjoyable character) is that his lines are obviously modernized for the 1949 time, but they somehow work? As in, they work to portray a charismatic schemer. It’s a weirdly good (?) way to make us see how someone like that could navigate all the political changes and survive so many dangerous moments.
