In the presented situation, are you obliged to yield way to the vehicle coming from the right?

In the photo you are driving along a street in a town and approaching a junction; on the right there is sign D-1 "priority road", and at the entrance of a side road on the right there is a red car. You are not obliged to give way to the vehicle coming from the right. The answer is: no.

The Regulation on road signs and signals states that sign D-1 marks the beginning or continuation of a priority road; drivers on roads joining it have sign A-7 or B-20 in front of them and must give way to vehicles travelling on the priority road. The right-hand rule from the Road Traffic Act works only at junctions where right of way has not been set by signs, so it does not apply here - the red car on the right waits until you have passed. This does not release you from the obligation to exercise particular caution when approaching the junction: the principle of limited trust tells you to check whether the driver on the right is really waiting, and not just assume that they know the signs. If they moved off, you would brake, even though you have right of way. You drive smoothly, without stopping for no reason, because giving way unnecessarily on a priority road confuses others.

Legal basis: § 43 para. 1 and § 5 para. 5 of the Regulation on road signs and signals; Art. 25 para. 1 and Art. 4 of the Road Traffic Act (Prawo o ruchu drogowym)