Is it a civil airport/airfield open for traffic other than gliders, does it for instance got an ICAO name or is it just a strip of grass
(I don't know about glider strips in Germany) ??
I landed at Glücksburg Rescue Station. Nice paved helipad with all the fancy lights, own radio frequency, firesquadron on standby at landing etc. etc., but its not a civil/public helipad
(only two civil helipads in the entire Germany excist, I was tolled). And since it wasn't a civil/public place, the above mention authorisation for off-airport landing was required ..
Better ask the local authorities before hand. Rüdiger in Schleswig Holstein, if you are going there, is very helpful and speaks fine English ..
Last thing you want is 5 min. after landing a BO105/EC135/EC145 Polizei helicopter, asking you
"Zo wher do yi zink yi going??" 
..
- madman