The execution in La Passion de Jeanne d'Arc

The execution scene in La Passion de Jeanne d’Arc always struck me as being incredibly realistic. How was that done? More specifically, what is the body?

I’m not talking about the starting bits, that’s clearly Falconetti and she’s clearly not on fire. The parts after that, once Joan’s lost consciousness and slumped over.

I know the blood-letting scene is realistic because it is real. But obviously they couldn’t burn a person at the stake, even if it was just an extra. Still, the body looks so unbelievably realistic. It’s one hell of a dummy (unless it’s a cadaver).

Anyone know how the effect was done? The DVD commentary made no mention.