Crusader era coin?

Anybody recognize this?

I bought a lot of 21 uncleaned Roman coins on ebay, and found this in the mix. Definitely not Roman, I'm thinking crusader era? Unfortunately the obverse is all gone, not sure if it can be ID'd from the reverse only. Copper, 0.75g, 5/8" on the diagonal

No idea but in the side with good conservation, what its inside of the shield seems the french flor de lis, isnt it? Can be an start to search