Free Trading Zone, Hamburg
A large part of the port of Hamburg is a 'Free Trading Zone' - so it may happen, that you enter that port-area without seeing any controls but you might be checked for cigarettes,alcohol,drugs..., when you are leaving that area again !!
better watch out for these signs at many places around the port of Hamburg ! In general the freeport may be entered, when you walk or drive through the "Alte Elbtunnel" and there are some other gates to enter the Freihafen south of Hauptbahnhof.
There will be cameras watching you and maybe they will decide to check you, when you are leaving again. Entering Freihafen is mostly no problem at all !