What is the right course of action here?

In this scenario, you must allow the vehicles indicated, specifically the yellow car and the blue truck, to proceed. Under German traffic rules, when you encounter a situation like this, right of way generally prioritizes those already in the intersection or those traveling straight ahead over turning vehicles.

By allowing both the yellow car and the blue truck to pass, you ensure safe traffic flow and comply with the regulations governing yielding to vehicles in clear circumstances. Ignoring these rules could lead to accidents or confusion on the road. It's essential for drivers to be aware of all vehicles when making decisions at intersections, ensuring they adhere to the correct right-of-way principles.