תרגום - יוונית-צרפתית - Ο παππάς ο παχύς έφαγε παχιά φακή.

Not a tongue twister in French though, I could listen to the Greek sentence using google translator, 1,2,3,4,5,6,times and I still don't feel like being able to pronounce the whole sentence!

I don't think there is a tongue twister in French which has a similar meaning as in Greek! It's very funny, even Greeks can't pronounce it right when talking fast! I have another one too, much more difficult, try it in google translator as well: Άσπρη πέτρα ξέξασπρη κι απ' τον ήλιο ξεξασπρότερη!

Yeah! this one's harder again to pronounce!
Same here, even a dozen times in loop is not enough to get the whole sentence!

Greek is a difficult language anyway, but it also contains all the grapheme sounds existing, so it is much more easy for us to learn the correct pronunciation of foreign languages! If you want more tongue twisters in Greek, let me know, but remember that they are difficult!
PS: the literal meaning of the last one I sent you is: white stone, so white, even more white from the sun!