Lovely tank, most likely French, based on the text on the cap. Check also out the mixing pen on the fuel cap. Reservoir dimensions/measurements are 15x35×42cc = circa 22liters
Original Ki-Gass Fuel Primer stamped 1940 for a Royal Air Force Army Navy Rolls Royce Merlin Engine. From RCAF (Royal Canadian Air Force) WWII Spares from a Hawker Hurricane Flighter plane that was built in Canada during the War. In excellent used condition.