Adding German city districts to a zone map

Hello,

I am trying to show districts of Hamburg on a zone map. There are seven official districts in Hamburg and Bing Maps recognizes them when I do a regular search on their service. However, when I type them into a PowerBI table and add them to a map visualitzation, one district stretches over the entirity of the Hamburg area. My table simply contains a field for the district and a field for the city, which always equals hamburg. I put the city field into the location part of the map and the district field into the legend part.

Am I making a mistake, or is what I'm trying to do simply not possible? Any help is greatly appreciated.