What is the correct course of action in this situation?

Your answer is correct because in this situation, the lane you are currently driving in will end after about 200 meters, as indicated by the lane reduction warning sign. According to German traffic rules, you should prepare to change lanes in a timely and safe manner, which means you wait until the lane ends and then move over to the right-hand lane smoothly—not too early and not too late.

Additionally, overtaking vehicles in the right-hand lane is allowed here if it is safe and the traffic situation permits. However, moving into the right lane immediately when you see the sign is not correct because the lane ends only after a distance, so an early lane change could disrupt traffic flow.

The key point is to observe the sign indicating a lane ends in 200 meters and plan your lane change accordingly, ensuring you maintain safety and traffic order. This understanding helps you manage merges smoothly and avoid dangerous or abrupt maneuvers.