"It was intended to fit the R 40 with the welded FCM turret in the second half of 1940, while refitting all existing R 35s with the longer SA 38 gun and bringing R 40 production levels up to 120 per month for the duration of the war. From January 1940, the vehicles of light tank unit commanders were gradually uparmed with the longer gun; but as absolute priority was given to tanks serving in armoured divisions, which were of the Hotchkiss type, of the 273 platoon, company and battalion commanders eligible in Renault units, only a few if any received this "R 39". "
and
"Postwar France
Some R 35s served after the war in the Gendarmerie, as "R 39s" refitted with SA 38 guns. They were phased out from 1951 in favour of the Sherman tank."
https://en.wikipedia.org/wiki/Renault_R35/ Robin