The world is a big place and there are as many regulatory agencies as there are countries with the means to establish them...
Drilling down into the specifics of each country and how they might view Hobby Drones will take some time.
There was some effort in 2010 on RC Groups to establish a list of international model aircraft regulations..
To save some effort regarding Germany (mind the date) HERE is a response from that thread.
Quoting from the post:
Here are the essentials as requested:
Altitude restrictions: depends on the airspace structure, but never more than FL 100
Speed restrictions: Not faster than 250 knots (approx. 463kph or 288mph)
Model size and weight restrictions: Only weight restrictions apply. Up to 5kg you don't need to worry much, unless you use an IC engine, where you need a permission when you are closer than 1.5 km to the next housing area.
Most model flying fields are cleared for models up to 25kg. Over 25kg and your model has to pass an inspection, needs registration and the pilot has to pass a theoretical and practical test.
Distances from airports that models can be operated: Minimum 1.5km from the border of an airport. Other limitations apply.
Insurance: Third party liability insurance for aviation is mandatory!
Wow. We don't require liability insurance in the USA for individual flying...yet. Oh wait, the AMA has this if your are flying according to their safety code. Go figure.
Agreed. The global approach to this discussion will never focus.
Let's stick to the US discussion.