These are open air cafes along the Rhine. It was cold and windy so not surprising that few were hanging out here but Lucas says Düsseldorf-ians have a huge tolerance for bad weather and fill up the places on weekends.
In the distance is the Rhine Tower (another symbol of Dusseldorf!). An explanation from a tourist website:
“The port holes on the tower form the world’s largest decimal clock. From top to bottom, vertically arranged yellow lights – separated by horizontal red ones – show decades of hours, single hours, decades of minutes, single minutes, decades of seconds and single seconds.”