Unidentified Ancient Gold Coin (Id: Medieval Re-Enactor Modern Wedding Gift)

Better-cropped photos would help a lot. It's hard to see the coin with this much white space.

I believe this is probably medieval, if real.

Unfortunately, it is not ancient, nor mediaeval. It is a modern token/medal, made to look like a mediaeval coin.

A few decades ago (at least, some time before 2009), a couple of French "Rennies" - mediaeval re-enactors - named Bruno And Karine seem to have decided to get married and hold a full-mediaeval-style wedding, complete with authentic imitation "coins" made from "copper", "gold" and "silver" to mark the event. The obverse has a mediaeval-coin-like cross with their Latinized names, BRVNO and CARINE The other side depicts a lion with the legend "CIVITAS AVMONT", the name of the French town where the wedding took place. This was apparently the commune of Aumont in the Somme Department, near the Belgian border.

I doubt your coin is actual gold, though perhaps a low-fineness version; you'd need to get it tested. I don't know what they actually did with these "coins", except perhaps give them out to guests.

References:
2016 FORVM thread with a silver example of the coin.
2009 thread on French-language coin forum, where unfortunately the old pictures have expired but the coin in this case was apparently copper.