Land use plan

If you want to know whether your property could be used as a building plot at all, you should take a look at the land use plan of your municipality.

The land use plan is the preparatory urban land use plan (urban development framework plan) of the municipality. It contains the urban development uses intended by the planning municipality and differentiated for the individual areas. For example, residential building areas, commercial building areas, utility areas, areas for public use, traffic areas, green areas, forest areas and agricultural areas.

The land use plan does not have any direct legal effect on citizens. No legal claims, in particular the right to a building permit for a specific plot of land, can be derived from its graphic and textual representations. However, it represents a binding programme for the administration and other authorities.

Indirect involvement arises from the fact that development plans, which contain legally binding provisions for all citizens, are to be developed from the representations of the land use plan.
In addition, citizens are indirectly affected by the approval of projects in "external areas" in accordance with § 35 of the Federal Building Code (BauGB), because in this case representations of the land use plan that contradict the building project would have to be held against it as an "impairment of public interests".

You can find more information on the urban land use planning here