Heard another one on 'Les Grosses Têtes' today:

On the war front, at night, a shell lands near a soldier. Succumbing to panic, the soldier flees… He runs and runs. Suddenly, in total darkness, he bumps into another person who is proudly standing there, unfazed.

"Excuse me, Sergeant."

"I'm not a Sergeant, Soldier."

"Sorry, Lieutenant."

"I'm not a Lieutenant either, Soldier. I'm a General."

"Really? I'm already that far from the front?"