Rene and Fanny have a mutual hatred of one another, despite constantly both being caught up together in the plans of the French, English or German intelligence- Rene because of how "out of the way" his cafe is, and Fanny because since she is by and large bed-bound, her bed, chamber pot, or other such boudoir-related object can be used to conceal or disguise a radio or secret weapon that would help their side win the war- although the more allies and enemies that approach Rene for help, the less clear it becomes whose side Rene is truly on.
Fanny is a misanthrope who constantly moans at anything or anyone she comes into contact with. Even her daughter, who is one of the few people who makes an effort to be nice to her, can do nothing to please her. Fanny is rarely seen not lying in her bed. Lt Gruber once found a book under her pillow with the title Wheelchair jujutsu which contained, among other things, 12 ways to disable a man with a crutch. It is hinted in a few episodes that she used to be a prostitute.
She mentions in one episode that she used to have a relationship with Vincent van Gogh (she called him Bobby).