Denmark
You can read the current rules on RC flight here: Bestemmelser for Civil Luftfart (danish)
Safety distances
Minimum distance to public road or buildings is 150m.
Max flying height is 100m above terrain.
At least 5km to public airfield (8km if military installation)
No flying over populated areas, or areas where a lot of people is gathered (festivals etc)
Weight
Aircrafts (helicopters, etc) weighing 7kg or less (in total, battery and payload included) can be flown without a license.
Spectrum
You must follow Lov om radiofrekvenser at all times.
In short, stick to 2.4GHz and 5.8GHz
FPV
Only allowed with spotter. (you must maintain visual contact with the drone at all times)
Commercial
Here is everything you need to know about commercial flying: Erhvervsmæssig mv. brug af ubemandede luftfartøjer (UAS/RPAS) i Danmark
Liability
You are liable for any damage caused by your RC craft. note: your regular insurance (ansvarsforsikring) will most likely NOT cover any damage caused by your craft. You get cheap insurance through you membership of the organization "Modelflyvning Danmark", so for hobbyist, this is the way to go. If you fly commercial you should get insurance from an insurance agency specialicing in aviation.
Helpful links
Landsforening
Danish summary of laws governing UAS
Is commercial flying allowed
