Oh my very spoily this trailer. I had a lot of fun just watching it without any previous background (but then again i never watch trailers on purpose). Only thing i knew was "its a French movie about modern subs" which is an instawatch anyway for me.
Oh and Aktung thanks for the recommendation, havent seen that one yet. Generally im a bit rusty with WW2 stuff. Feels like theres been a bit of content recently for uboat fans (be it movies, series and games) but theres been a bit of a draught in modern sub genre. Wolf's Call scratched that itch real good