Laws, courts and authorities
permit-free
In short and in plain language
Permit-free means you need no permit to build something.
Each state in Germany sets which jobs this is.
Other rules still apply. You must still keep enough space to the plot next door. And nature is still protected.
Definition
In building law, permit-free (German: verfahrensfrei) means that a project needs neither a building permit nor any other procedure with the building authority. Each German state defines in its building code which projects qualify; in Lower Saxony this is the NBauO. Other rules such as boundary distances, neighbour law or nature conservation still apply.