Atom.rpg.post.apocalyptic.indie.game.v1.185-gog...

You can sell him up to 500 pieces of wastepaper.

In the hotel at Krasnoznamenny, you will encounter a investigating veterans. He is looking to buy used paper to send back to his hometown, where there is a shortage.

Thoroughly search desks, cabinets, and bookshelves in abandoned buildings and bunkers. ATOM.RPG.Post.apocalyptic.indie.game.v1.185-GOG...

Alternative history 2005, following a nuclear war in 1986 that devastated the USSR.

The "useful paper" in (version 1.185-GOG) likely refers to Wastepaper , an item used to complete a specific side quest in the city of Krasnoznamenny . The "Wastepaper" Quest You can sell him up to 500 pieces of wastepaper

Wastepaper is a common "junk" item found throughout the Soviet Wasteland. To gather enough for the quest:

The photographer increases his purchase price each time you bring him a new batch of paper. The "Wastepaper" Quest Wastepaper is a common "junk"

A turn-based indie CRPG heavily inspired by the original Fallout series.