The underground french resisitance is a period of history that I'm greatly interested in. I just finished reading "Paris Underground" by Etta Shiber. It was written while the war was still underway and she had been traded for another german woman who was a war prisoner in the US. Etta and her friend Kitty Beaufoux were caught helping English soldiers sneak out of occupied France. They helped over 150 young men. The book is fascinating as it explains real personal experience.
You can read the book here.