Why is this film less known than "Casablanca" or "The Third Man"? Maybe it's because many see it as "just" a comedy, which these people consider a "lesser" art-form. In my opinion they miss that the brilliant screenplay just smoothes out the edges and puts some very sharp and witty dialogue on a plot and setting, which is actually very "noir"ish at heart. I guess it takes someone like Billy Wilder, who returned with this film to a city where he once lived (and that he loved), to discover the comic effect of a "weight-challenged" GI with a bunch of flowers and a dachshund on the lead walking to his "Fräulein" through the ruins of a bombed-out street. Less ingenious directors probably would have indulged in mourning and (self)-pity, which is exactly why many German movies from that immediate post-war time are unwatchable (unless you are fascinated by the morbid beauty of the ruins and rubble).
As a German my only minor quibble with "A Foreign Affair" is the German dialogue (not the occasional "Strudel" and "Gesundheit" from the American actors, but the actual German by supporting actors and extras): in most cases it sounds embarrassingly dumb, even feebleminded. Apart from one scene that has the same level of cynicism as the English dialogue (the choleric policeman asking "You live? Do you have permission?" after the "Lorelei" round-up), only Marlene Dietrich is allowed to talk normally.
Otherwise it's one of Billy Wilder's best films (which is synonymous with being one of the best films of all time). Unfortunately you don't get characters like Captain Renault ("Casablanca"), Major Calloway ("The Third Man") or Colonel Plummer ("A Foreign Affair") anymore in contemporary films. A pity!
