In Germany, what does a blue circular sign with a white bicycle symbol designate?

In Germany, a blue circular sign with a white bicycle symbol designates a compulsory cycle path.

The blue circle indicates a mandatory instruction, while the bicycle pictogram identifies the road user concerned. Where this sign applies, cyclists are required to use the designated cycle facility rather than continuing on the adjacent general roadway, subject to the detailed circumstances and wording of German traffic law.

The sign should not be confused with a blue rectangular sign showing a bicycle route or with a red-bordered circular sign depicting a bicycle. A red-bordered bicycle symbol is associated with prohibition, whereas the blue circular version communicates an obligation. Shared pedestrian-and-cycle paths use a combined pedestrian and bicycle symbol, sometimes separated by a line.

German signs follow a systematic distinction between mandatory blue circles, prohibitory red circles, and warning signs. Road markings, supplementary panels, and the physical condition of a cycle path can affect how a particular location is interpreted.