I find the trio fitted with this chair (FN, Sarolea, Gillet) quite difficult to identify if the engine and front hub aren't visible but had generally regarded the Bosch Horn below the headlamp as an FN characteristic....or did Gillet use alternative positions ?
The forum pic also seems to have a winged filler cap. In the photos that I've seen, Gillet seem to have used a plain variety ?
I've copied the original to here as it will probably disappear shortly.