This vehicle paper model is a Tatra T3, the papercraft is created by Jan Fabian and Squirrelfish, there are 1:100 and 1:300 two scale versions available.
There are also CKD Tatra T3SU Tramcar Paper Model Ver.1 and Ver.2 on the site available.
You can download the paper model template here: CKD Tatra T3 Tramcar Free Vehicle Paper Model Download [Yadi.sk] [Box] [Gavitex] [Ge.tt]