I sometimes come across jokes Americans do about the French army, on how the French will surrender quickly in a war, etc. That is not common at all in Europe.
Being a bit of a military history buff, I wonder where this comes from: is it only related to the surrender of the French Army in 1940 ? or to another event in history ? Any idea when they appeared ? Is the stereotype about French surrenders still a "serious" opinion among Americans nowadays ?
Note: I am not French myself.

(比利时人)我时不时会听到美国人编的针对法国军队的笑话,说的是法国人往往会在一场战争中迅速投降,诸如此类。而这种笑话在欧洲并不常见。
我也算是个军史爱好者,我很想知道这些笑话的出处:只是因为法国军队在1940年投降了吗?还是和另一个历史事件有关?有人知道它们是在什么时候出现的吗?,今天的美国人当真抱持着 “法国人爱投降”这种成见吗?
注:我不是法国人。