1) Hidden from the Nazis
In fact Citroen didn't want the car to fall into the hands of Nazis so several were buried at secret locations, one was disguised as a pickup and the rest were destroyed. In fact it was believed that only two original prototypes survived and were found again until three more were discovered in a barn in 1994.
2) It had to carry eggs off-road without breaking them
The car was the brainchild of Citroen Vice-President Pierre Boulanger who wanted to create a simple and affordable car that small farmers could use instead of the horse and cart still widely used. The design brief for the car stated that it should be a low-price rugged 'umbrella on four wheels' that would allow farmers to transport 50kg of produce to market at speeds of upto 50kph across muddy unpaved roads. It would have to sip fuel at a rate of just 3L/100km. More famously it should be able to carry a basket of eggs across a ploughed field without breaking them!
3) James Bond drove one
Tin-Tin was used in advertising, but probably the car's most successful product placement was in 1981 in For Your Eyes Only. Roger Moore's James Bond resorts to using one to escape the baddies in their Peugeot 504 saloons, storming down through a Spanish olive farm. For the film the car was equipped with a more powerful flat-four engine from a Citroen GS, although the special edition models commemorating the movie role – complete with 007 decals and fake bullet holes – offered the regular flat-twin.
4) Iran's own 2CV
The 2CV was also made in Iran where it was called the Jian (Fierce) as part of a joint venture with Iran National, although after the 1979 revolution the Iranian company just carried on making the cars without Citroen's involvement.