I know another French joke that is extremely targeted in exactly the same way. It's from Canada, and it pretty much only works when read aloud.

    Eh, did you notice there's no h in 'ere?
    It's 'cos they left it in h'Ottawa.

For people who don't know the accent, French people don't typically pronounce the h initial in words like 'here', (or 'humpty' for that matter) and they add an h to vowel initial words like 'Ottawa'.

Another joke we have refers to how the French pronounce the English word "happiness."