Who is Marie-Claude Carpenter and Betty Fernandez from The Lover and what is their importance?

Marie-Claude Carpenter was an American woman from Boston, living in German-occupied Paris during World War II. She was an expatriate women, who maintained a proper, though somewhat artificial, appearance during the war. Her home, none-the-less, was a place where various people congregated to dine and meet. The discussions in Carpenter's were primarily political, and she was suspected of being a Nazi collaborator.