The sign is called "Prohibition for cycling traffic." This traffic sign indicates that cycling is not allowed in the area it is placed. It is generally used in pedestrian zones, roads where cycling could pose a danger to pedestrians or vehicles, or where a specific local regulation requires the prohibition of bicycles.

Cyclists must dismount and walk their bikes in these areas, and they should look for alternative routes or designated bike lanes where cycling is permitted. It is important to obey this sign to ensure the safety of all road users and to comply with local traffic regulations.

If you have any further questions about traffic rules or another sign, feel free to ask!