It may be the Renault prototype of an SPG based on the FT chassis - this design was rejected. There was also a similar prototype with a 105mm howitzer.
More on the Renault FT chassis SPGs at: http://www.landships.info/landships/tank_articles.html?load=tank_articles/Renault_SPGs.html
Regards,
Charlie
ps: The tank was called the "Renault FT" - FT-17 is an incorrect designation.
EDIT: Turned de link into a link
I found this picture with an Renault FT-17 with (i think) an Canon de 75 modèle 1897. Can somebody tell me more about it?
Regards
Denis