Does the horizontal sign indicate the place to stop in order to yield the right of way?

Why?

The solid transverse line P-12 marks where you must stop for the visible B-20 STOP sign. Stop before the line and give way to vehicles on the priority road. You must stop even when the road is clear.

§ 89 ust. 1 oraz § 21 ust. 1 i 2 rozporządzenia w sprawie znaków i sygnałów drogowych, P-12 i B-20