German Environmental Protection Law §36
Applies to camping in tents or other moving vehicles made for camping:
(1) Tents and other moving vehicles such as campers may only be set up and used in a campground. (with the exceptions below)
(2) Non-motorized travelers may sleep overnight in a tent or camping vehicle outside of a campground on public or private property if they are authorized privately or there are no special regulations to the contrary. On property in a close residential area, tents and camping vehicles are allowed to be used only for non-public reasons, but for no longer than 6 weeks. Local community regulations may prohibit or limit this.
(Don Feidner's comment: I understand this to mean not only on private property when you are invited by the owners to pitch your tent for a night, but also off-road, next to bike trails, in forests or other open non-residential areas, and away from places where you might disturb others. A policeman explained to me that gypsies like to put their vehicles in a public parking lot and live there for several months. This law prohibits that practice.)
(3) Outside of campgrounds, the use of tents and camping vehicles can be authorized for no more than 5 tents or camping vehicles up to six months if:
1. there is no negative impact on nature or the general well-being of persons living in the area.
2. the area used and the area surrounding it is kept clean and returned to an orderly condition when leaving.
3. proper sanitary conditions and other public security measures and proper conduct are adhered to.
Sleeping in tents outside of campgrounds is generally allowed under the following conditions:
- Camping only for individual travelers and families (not for groups), who are traveling as boaters, cycle tourists, or hikers are underway.
- The tent size does not exceed 3 x 3 meters
- Camping is limited to a maximum of one night
LINK to German Law Text - I recommend you print this page and take it with you.