This movie could been perfect for a great double twist (SPOILERS INSIDE)
I love double, triple and multiple twists plots, and this movie got the 1st half opened for a great at least double twist. Instead it had only one twist, that can been spotted miles away from the first 10 minutes of the movie.
The 2nd half let us a bit wondered if she was indeed a German spy or not, with a drama at the end when she kill herself. I would've changed the script to instead have a heavy thriller action part where Pitt character would chase around some more, instead of stopping at only one drunk guy in a French jail, to actually have more digging to do, then come to conclusion she is a German spy, and kill her as the law implied by Frank was. And then the double twist to be when Monday arrives Frank to tell him no message was passed and he killed his wife for nothing. Now that would been a good ending with a nice double twist.
But nah, Hollywood is too dumb for greatness so instead we got a mild entertaining movie which barely can pass for me.
My 2 cents.