The sign you mentioned, Symbol Notice 1010-51, indicates a "Parking" area. It signifies that parking is allowed in the designated area under certain conditions, which might include time restrictions or the requirement to display a parking ticket.

In many cases, you may need to follow specific regulations regarding when and how long you can park there, and whether any fees apply. Always pay attention to any additional signs or markings that provide further details about parking restrictions or requirements in that area.

If you have any further questions about German traffic rules or need help with other signs, feel free to ask!