20 000 Lira fine is for not to register Police ID report system and enter the short term guests.
Police will send file to tax office and tax officers will fine them too (If this is a short term commercial rent)
As Scunner point out you must be sure about registration to police.
There is no licance or certificate showing registration to police yet,but you can ask screen shot of police ID report system.
On Id report system address of short term rental property can be seen.
Here is the ID report system KBS(Kimlik Bildirme sistemi) screen photo sample