My original thought was it was a panther as these are usually depicted as maneless lions and, to me, it looked more like that. However it looks like panthers are spotted in heraldry etc and often have what appears to be fire coming from their mouths and ears which this big cat doesn't.
That left maneless lion or a leopard and I would expect a 'lion' to have mane and all other lions seem to have one but I thought leopards had spots - in heraldry it seems not. It is well known that the English Arms are referred to as three lions however I found it interesting that these cats were called leopards until the late 1300's and it is only later than they became lions to the English - with the French and neighbouring nations still referring to them as leopards.
A possible reason for this is that that leopards were thought to be a result of the mating of a lion and the mythical Pard, with the offspring therefore being leo-pards. This mixed Heritage
meant that leopards could not have young and was therefore also used as a term to describe someone born of adultery as such children were left out of the line of succession.
It would not surprise me that, for such reasons, the English switched to calling them lions whilst the French were still calling the English leopards and hence 'barren bas*&"ds', or whatever the equivalent is in French!
As this medal was struck in France, and blaming the English for ending the Treaty of Amiens, I am therefore going to refer to the big cat as a leopard from now on - of course all this could be complete rubbish and it is the local farm moggy!