Dusseldorf is quite the shopping destination. Since the weather is not always the best in this part of Germany, keep in mind that you can complete all of your shopping in the indoor Schadow Arkaden http://www.schadow-arkaden.de/. Once  a month look for " Verkaufsoffener Sonntag", as stores are typically closed on Sundays in Germany, new laws allow them to open for certain Sundays each month.

 Head to the Konigallee for exclusive shopping or just to window shop. Many major luxury brands(LV, Chanel, Gucci etc) have stores there, as well as some of the best department stores in Germany (Seven,Kaufhof,Koe Galerie). All the references to "cartwheeling" dates back to the days when boys would do cartwheels down the street to entertain shoppers and make a few extra bucks.www.koenigsallee-duesseldorf.de

For less upmarket shopping (think of C&A, H&M) but also some quite nice department stores(P&C, KAufhod, Karstadt) head to the nearby Shadowstrasse, the street with the biggest revenue in Germany.