Page 14 from French Tanks of Word war 1 (Osprey-New Vanguard n° 173 ), Steve Zaloga submit a good photo from Aberdeen's Schneider (now in Saumur's museum since 1985).
On rear tank, is written : " FXCV 217", which is, perhaps :
Foreign Exchange Combat Vehicle (number) 217
If "217" is well the end of the original french tank serial number, this tank is the number 61217.
Inside the Groupe AS 10, this Schneider was the third tank from the second Battery.
The tank commander was the Maréchal des Logis Rochard and its last fight was Méry on June 11, 1918.
Some other information here, on forum "pages 14-18"