What is the right course of action?

In this scenario, you're facing a situation governed by a yield sign. According to German traffic regulations, when you encounter a yield sign, you must allow other vehicles with the right of way to pass through.

The correct actions in this situation are:

1. Allow the blue truck to pass through: Since the blue truck is likely on a more prominent road, it has the right of way.
2. Allow the tractor to turn: As the tractor is also in a position where it needs to turn, you must permit it to complete its maneuver safely.

Failing to recognize the right of way for these vehicles could lead to dangerous situations. It's important to understand that even if you see an opportunity to go, safety and adherence to traffic rules should always take priority. Always assess the signs and surrounding traffic to make the best decision.