I looked for it but I couldn't find it on DT. It begins with:

Ami, entends tu le vol noir des corbeaux sur nos plaines?
Ami, entends tu les cris sourds du pays qu'on enchaine?

It is sung by Ives Montand, I have a faint memory of the song, as my das had a tape recorder - not a cassette recorder but a huge tape recorder - with some songs that could not be heard on the radio, and we used to listen to them, very, very low, so no neighbour would hear. By the way, does anyone know where and how can I get the record (CD I mean)?