I would recommend looking into Slovakia's aerial regulations, as they should have a website similar to the FAA (US). Have you tried searching for drone laws in Slovakia? You can also check the regulatory links via our FlySafe site to see if Slovakia is there:
Slovakia has no drone law. Therefore theoretically old airial photography regulation would apply where you need to ask for permission at some government minister.
However in reality no one cares about this.
But in case of an accident it may be a problem as insurances could refuse to pay claiming the flight was not legal also haevy fines could be implied IF something goes wrong.