Hi Jorgen,
thank you for your answer!
If I understood you right, if my kite is under 2,5 kg I do not have to mark it and still may fly above 45 meter?
But how high ? I guess less than 1000 feet?
Because then there are sometimes airplanes flying around ... 
And can you tell me wich goverment authority decides where I am allowed to fly ... (parks, beach, etc.)
In Danmark it would be "Naturstyrelsen", who is it in Sweden?
(Do you have a contact for me?)
Hi Jens,
It is correct, if your kite has a mass of 2,5 kilo or less no marking rules apply. No maximum height of flying is specified. Of course it is not a good idea to fly around aerodromes. You do not need any permission to fly in public areas in Sweden.
Best regards
Jorgen Andersson
Senior Aerodrome Inspector
Sectorial Focal Point EU-ADR
the Civil Aviation and Maritime Department
Office: +46 10 495 36 97
Swedish Transport Agency
SE-601 73 Norrköping
http://www.transportstyrelsen.se
Phone: +46 11 771 503 503
Wow, keine Höhenbegrenzung in Schweden und fliegen überall erlaubt (Öffentlichkeit, auf Privatgrund nachfragen) ...
Viele Grüße, Jens