Way back in the 1960's I managed to spend several days in hospital in Espalion, on the river Lot in France, having succumbed to some form of dysentry. My mate Richard was befriended by a bunch of others on holiday, and when I got better, we hung about with them for a couple of days. One of these guys had a guitar which at the time was vastly intriguing for us both, and he serenaded the group with an assortment of French and English folk songs. The only song which stuck in my head was a long French one with a distinctive chordal riff between verses. We returned to England both vowing to get guitars as soon as possible.
The other night I watched Les Plages d'Agnes, a film by Agnes Varda,and to my amazement this song popped up on the soundtrack at the point where her family moved to Sète during the war. George Brassens (a native of Sète) got a mention at another point in the film, so it didn't need much detective work to track the song down.
Hearing it again takes me back to the ruins on the hill in Espalion with swallowtail butterflies everywhere, and a very tender stomach.
Here's a page with it all in.