The sign you mentioned, Note Symbol 1010-12, is a warning sign indicating that there is a temporary traffic signal ahead. This sign is used to alert drivers to the presence of a traffic light system that is not usually there, often due to roadwork or other temporary traffic management measures.

When you see this sign, you should be prepared to encounter a traffic signal shortly. It is important to approach with caution, reduce your speed, and be ready to stop if the signal turns red. Always obey the traffic signals as they are in place to ensure the safety of all road users, including pedestrians and construction workers.

If you have any other questions about German traffic rules, feel free to ask!