Good Morning - medallions like this are not common. Oscar Roti (born in Paris) was the most reknowned medalist of the Art Nouveaux era - for those curious a medalist is an artist who designs medals, plaquettes, badges, coins and similar small works in relief in metal. Roti was largely responsible for the renewal of medallic art at the end of the nineteenth century. If it is Roti who designed the medal which is highly unlikely then you are very lucky indeed. The medal would be signed with his signature. Can you see a signature anywhere on the front? The subject isnt clear but looks to be art nouveau - have you tested the metal yet? Is there anything on the reverse? The photo is not clear unfortunately.
