If we don't want to cross the river to see the sunset, we go to a little platform next to the chocolate museum. Since it's built like a boat & located right next to the river, you get the feeling to be on board. You'll get a great view of the dome, the bridges & the boats. And in summer you might even witness a free open air salsa party.
The platform is free, close to the city center and agood spot to see the sunset without taking a trip across the river. In combination of a walk along the Rhein and to the Rheinauhafen, this is the perfect actitvity in the evening.
There are quite a few steps to climb to get all the way up to the platform. Go around the steps to see a cool statue on the bottom of the platform.