Having lived through that period in London, whoever was responsible for costumes did no real research. No one in England or France had the new outfits worn by everybody.
The actual SOE offices were sparse with minimum furniture and none of the interior design luxury with oil paintings and side lights of an interior design magazine. The attempts to have actors appear to speak French
was pathetic. Phone accents with too many 'Bon Chance.' As for the doctor taking someone to lunch, both agents, in occupied France was ludicrous, with wine and chocolates included.
The remarkably brave Noor Inayat Khan Died an even worse death in Dachau than conveyed in the movie. And for the truly amazing actual story of Virginia Hall. Do read it up. Extraordinary.
Derek