Hamburg's first (and my favorite) discgolf course is located in a stretched out public green space in the (mostly) business district City Nord. As such, it gets mowed regularly and you are not bothered by the masses that flock to the adjacent Stadtpark each summer. There is still your eventual dog walker or picnic crew, but most people are getting used to Discgolf being a thing and a friendly word will clear your fairway the majority of times. The course is easily accessible by car or public transportation (U1 Sengelmannstrasse, coming from the south it's also a nice bike trip or walk through the Stadtpark).
It has seen recent changes in layout due to construction by the city, as 2 original holes had to go. But the local Discgolf club does an outstanding job of rolling with the punches and included 2 alternative basket locations and even added 2 more at HDI campus (making this a #16 hole instead of the original 14). The 2 new HDI baskets (#14 & 15) seem a little detached from the course at first, but make for a really nice addition.
Hole # 10 is somewhat of the signature hole and played from top of the bridge (despite the tee sign being at the bottom). #11 is an island hole that has some unique wind conditions, as the gaps between the high buildings shape the wind and make it sometimes come from different directions in different sections of the shot.
If you need to stack up on drinks or snacks, there's a gas station just 150m on the right from hole #10 tee.
Lost and found discs can be dropped / retrieved from a box on the rear of the course sign at #2 basket.

This course can be a little hard to navigate at first. Some of the original tee signs have been vandalized, the numbers on the baskets don't always match the tees and the new pin locations and recently added holes only have spray paint marks on the side walk to indicate tee positions. They are also not shown on the 2 old area maps on the course, but an updated map can be found here: https://www.discgolfclubhamburg.de/parcours Several holes require spotting and OB is used quite widely to block off sidewalks for safety precautions. Hole 10 basket has somewhat of a dog shit problem, other than that the place is pretty clean. You can lose discs at #2 in the thorny bushes / stingy nettles hellhole to the left, in the bushes behind #11 (or spike hyzer on the rooftop right) and at the bottom of the bridge for #10.

I love this course simply of how well it utilizes the area provided to create an entertaining discgolf experience right in the city. Each of the holes seems somewhat unique and the little hills and ditches, as well as the bridge make for a nice landscape variation in a rather flat area. Walking up from Barmbek, I usually start my round at #11 to not having to cross the entire course to get to #1. I recommend to play the first round with someone knowing the course, just to get the layout down (or ask people playing, discgolfers are usually nice people. Once you know it, it comes pretty natural. I try to get my round in whenever I can.