What is the right course of action here?

In this scenario, the correct actions are to allow the blue car to pass and to stop at the stop line.

1. Allowing the blue car to pass is crucial because it indicates that the car has the right of way, ensuring safe and efficient traffic flow. According to German traffic rules, vehicles already in the intersection or approaching from a primary road have priority.

2. Stopping at the stop line is also essential. The stop sign requires you to stop completely and assess the situation before proceeding. This is important for ensuring pedestrian safety and observing traffic regulations.

Choosing both options ensures compliance with traffic rules, prioritizes safety, and maintains orderly traffic.