Hehe, your right TOS! Its the 1955 prototype of the Batignols Chattilion 155mm and it was cancelled in 1959. Over to you my friend!
AFAIK there wer two versions of the AUTOMOTEUR BATIGNOLLES-CHATILLON 155mm, the 1955 one shown and a 1958 one with automatic loading that didn't go further than a wooden mock up. Next one View attachment 12614
Really close so I will give it to you though it's really the the 84mm (20 pounder) armed Pz 58 rather than the 105 armed Pz 61. The L7 gun of the 61 had a very recognizable smoke extractor.http://www.massimocorner.com/afv/Surviving_Pz58_Pz61.pdf