The Kinder-yorn song GerryM links to is quite nice though it doesn't appear to me be the same as the lyrics Monique and Mama Lisa are seeking. This posting of Kinder-yorn includes English and French language translations as well as Yiddish and transliteration, a music sheet, glossary and links to recording http://yidlid.org/chansons/kinder-yorn/index.html. And on youtube there are other recordings, including one by Theo Bikel, though I have the radio on now and have not checked that they are the same song.