PSA, free-camping
A lot of tourists come to Norway to camp, having heard of Allemannsretten and thinking this means you can camp anywhere freely. Not everyone seems to have heard of the actual premise of allemannsretten.
Firstly: it only applies to "utmark" - wild areas. Utmark is anything that is not "innmark". Innmark includes yards, farms, "dyrket mark" which is agricultural land (meadows, farmed area etc), parks, industrial land etc.
This means that practically any area that appears wellkept and maintained is not utmark, and generally not for freecamping.
Places like Telegrafbukta or Charlottenlund are beautiful and well-maintained, and tourists sometimes try to use them to camp. But they are beautiful and well-maintained because they are city parks/recreational grounds. I don't know of any country where it is normal to camp at playgrounds or recreational grounds, and it certainly is not normal here.
It is an odd experience to go for a run at an outdoor running track in the middle of the city and see 4-5 tents pitched (including in the community Gapahuk), and then see someone in their underwear stumble out of their tent to pee on a tree (fyi: also highly illegal in Norway).
So, rule of thumb: Allemannsretten only counts in the wild (and if the area looks taken care of, it probably does not) - and there is no private house or cabin within 150m. Even then you can only camp in one place for 2 nights, and you must leave the place without a trace.
If you prefer to sleep on maintained grass with facilities, please go to a campground, not a city park or yard.