Toadfrog, having strained and scrutinized my memory for hours I remember that the song in einem Polenstädtchen indeed contains a verse vergiß Maruschka nicht, das Polenkind (never forget Maruschka, the Polish girl).
It is a pert abominable song about a girl seduced and betrayed by a "German grenadier". The girl finally committed suicide.
I never sang it because of the respect the women deserve; I heard it sometimes sung by enlisted men, but only when drunk. After a while I stopped this by asking: What would you have done if it had happened to your sister?
Especially the last verses are most detestable because of the choice of words, really chauvinistic and racistic.
These are the causes why I shouldn't sing it not only to a Polish audience, but never. It doesn't fit an officer and gentleman.

Wilfried