From Wikipedia article:
Occasionally language is unintentionally macaronic. One particularly famed piece of schoolyard Greek in France is Xenophon's line "they did not take the city; but in fact they had no hope of taking it" (οὐκ ἔλαβον πόλιν· άλλα γὰρ ἐλπὶς ἔφη κακά, ouk élabon pólin; álla gàr elpìs éphē kaká). Read in the French manner, this becomes "Où qu'est la bonne Pauline? A la gare. Elle pisse et fait caca." ("Where is young Pauline? At the [railway] station. She's pissing and taking a shit.") In English literature, the untranslated line makes an appearance in James Joyce's Finnegans Wake.
I've tried but failed to find the original source of the phrase.
Can this line really be found in Xenophon's (or any other ancient author's) works?