When France was occupied by the Germans in 1940, major French companies like Citroën were forced to produce equipment for the Nazis. Citroën president Pierre-Jules Boulanger (inset) knew he couldn’t just refuse to produce anything, but he also knew there was no way he was going to just roll over and build trucks for the Nazis. He decided to instruct workers to set a nice, leisurely pace when building trucks for the Wehrmacht (the unified armed forces of Nazi Germany). He also told them to move the little notch on the trucks’ oil dipsticks that indicated the proper level of oil down just a bit lower. By moving the notch down, the trucks wouldn’t have enough oil, but German mechanics would have no idea, because they had no clue the notches on the dipstick were inaccurate. After the trucks were used for a while and were deployed out somewhere crucial, the engines would seize up. That left a lot of angry, stranded, vulnerable Nazis, which was Boulanger’s objective. It was an ingenious sabotage and extremely cheap to implement.
