Jahnwiese

In the location's words:

Directly behind the south stand of the Rheinenergie Stadium are the ten grass pitches - seven large and three small - of the Jahnwiese. The facility is municipal property and can be used for a fee. However, the grass pitches are very quickly occupied.

The insider's tip: If you don't dare ask if you can join in the fun, simply walk west across the Jahnwiese. He is sure to find a suitable soccer field at the nearby Adenauer pond or on the many small meadows in the city forest.