Not seen le Silence de la Mer but the book was pretty good so I hope you got a chance to see it
If you have gone through the existing list, here are some more, some are probably hard to find
Un Ami viendra ce soir (Raymond Bernard) - Michel Simon is supposed to be really good in it
Vivre libre (Jean Renoir) - 1943 has a reputation for laying it on a bit thick
Les Portes de la nuit (Marcel Carné) - A bit dark and probably more occupation than resistance but it's supposed to have not been well received because it doesn't have a reconciliation message which was the done thing in 1946. Features a super young Yves Montand
L'Imposteur (Julien Duvivier)
Not French film but featuring French resistance
Saboteur sans gloire / Uncertain Glory (Raoul Walsh) - Errol Flynn reported to be really good in it
Bon Voyage (Alfred Hitchcock)
Since someone mentioned Casablanca, there's another Bogart : Passage to Marseille (Michael Curtiz)
Not 100% sure this one fulfils the brief but might be easier to source
13 Rue Madeleine - Henry Hathaway (
13 Rue Madeleine (1947) 6.9 | Action, Adventure, Drama )
TV rather than Cinema, but if you want pure fluff there's Gone with the Wind meets WW2 - there were legal wranglings - (the book sold like hot cakes when it came out in the 80s, very popular with teenage girls because sex scenes :-D) - the whole thing is available on you tube and Laetitia Casta is cast as the heroine