What is the right course of action here?

In this scenario, the yellow vehicle has the right of way as it is already in the intersection. According to German traffic rules, when approaching an intersection with a give way sign (as indicated by the sign in the image), you must stop if necessary and yield to vehicles that are currently in the intersection.

By allowing the yellow vehicle to pass, you ensure the safe flow of traffic. If you were to take the turn ahead of the yellow vehicle, it could cause a collision. Thus, the correct response is to yield to the yellow vehicle while you make your turn only after it has passed, maintaining safety and compliance with the rules.

Remember, it's important to always assess the situation and yield to those who have the right of way to prevent accidents and ensure smooth traffic flow.