I tried this in Argeles-sur-mer a few years back!
I cannot for the life of me remember what possessed me to order it, but never again! It arrived looking somewhat like a large grey version of a black pudding,sliced open so that the contents were spilling out onto the plate like someone had disembowelled a small animal. Mercifully, I had ordered it with a covering of mustard sauce which made it barely palatable, and i managed to eat about half before I came across a piece of what I think was pork, but it still had coarse hair attached, I conceded defeat at this point!
My wife later took great pleasure in reading aloud to me a graphic description of what i had consumed, from a guidebook - truly horrific