Thanks Guy. The most detailed account I can find is in La Revolution Francaise (Le Courrier et le Hasard):
But it doesn't state the identity of the regiment's flag, so it isn't complete.
If it was the 31st DB, I assume then this would have passed to the 7th Line. So I wonder if the heart was then attached to the 7th Line's flag.
I wonder if anyone has a history of the 7th Line and can check - or was it some other unit which absorbed the 31st (if indeed it was the 31st which had the heart ....). Mysterious.