In general, shops are open at the times detailed below:
Monday to Friday: 9 am – 8 pm (09:00 bis 20:00 Uhr)
Saturday: 9 am – 4 pm (09:00 bis 16:00 Uhr)
Department stores and big super market might be open until 8 pm (20:00) even on Saturdays.
In Duisburg If you're looking closest Halal Meat Markets and Halal Grocery Stores then "Hochfeld Duisburg" is one of the best place to buy those things. There are several ways to reach "Hochfeld" but simple way is that, you can take 903 Tram/Strassen Bahn from Duisburg Main Station/Hauptbahnhof to Destination/Richtung "Mannesmann Tor 2" and after 7 minutes you have to leave Tram/Strassen Bahn at "Pauluskirche" stop/Haltestelle. Shops are closed on Sundays and public holidays. Exceptions are gas stations, bakeries, kiosks and some shops located in the main train stations.
Most shops accept credits cards and EC-cards except small grocery shops as well as Kiosks and Bakeries in which cash payment is expected.
Other shopping areas where you can buy daily food & other stuff.
more detail coming soon!