To unlock the "Republia Token" trophy in Papers, Please, you must help a Republian man through the border and then return his collateral when he comes back with the right papers.
The event starts on Day 21 (December 13th). The sixth man through your post is Danic Lorun. He only has a passport and no supporting documentation. Point this out to him and he'll make you a deal, passing over his fancy digital watch as collateral. You must approve him.
On Day 22 (December 14th), the ninth visitor to the booth offers to buy the watch from you. Do not give him the watch.
On Day 23 (December 15th), the fifth visitor also tries to buy the watch. Do not give it to him. Right behind him, the sixth visitor is Danic. Give him his watch and he will give you some money. He will then claim that the watch is scratched and demand the money back. Give it back. Danic will change his mind, return the money and give you a token. The trophy will unlock too.