This paper model is an ISU-152, a Soviet multirole fully enclosed and armored assault gun or armored heavy howitzer, also also capable of serving as a heavy tank destroyer used during the Second World War, the papercraft was shared by Ak71, and the scale is in 1:72.
There are other versions on the site:
WWII Soviet ISU-152 Armored Assault Gun Paper Model
WWII Soviet ISU-152 Armored Self-Propelled Gun Ver.2 Paper Model
WWII Soviet PT-76, IS-2 and ISU-152 Tank Paper Models
You can download the papercraft model here: WWII Soviet ISU-152 Armored Self-Propelled Gun Ver.4 Free Paper Model Download [Box] [Gavitex]