Treasure hunting by the Thames HD

3 1/2 hour hunt produces an old french coin. Anyone able to ID,please I have been detecting for 2 1/2 years with my ETrac and SunRay probe. I am out normally about 20 hours a week andI have 4 gold and silver finds being analysed at the British Museum under the Treasure Act more info at http://www.metaldetectingagency.co.uk/ See my main metal detecting UK website/metal detecting ring/jewellery finding service in London or Essex at http://www.metaldetectingagency.co.uk/ and my 5 Treasure Act 1996 finds and roman zoomorphic mount at http://www.metaldetectingagency.co.uk/treasure-act-finds-and-museum-pieces.html