Does this horizontal sign define a place of obligatory stop, even if there is no vehicle approaching from either side?

Before the junction there is sign B-20 "STOP", and a thick solid transverse line is painted on the roadway. This is the mandatory stop line P-12. The word "mandatory" says it all: you always stop before it, even if the priority road is empty and you cannot see anyone.

The STOP sign prohibits entering the junction without stopping before the priority road, and you must stop at the place marked for this - precisely by line P-12. Stopping means bringing the car to a complete standstill, not slowing down to a few kilometres per hour. Only after stopping and making sure that you will not cut in front of anyone do you enter the junction.

Legal basis: § 21 para. 1 and 2 and § 89 para. 1 of the Regulation on road signs and signals