Shops in Germany do not have the same opening hours. Normally, only during public holidays, shops remain closed. However, there are a few exceptions to this rule (generally open on Sundays and public holidays are bakeries, shops inside railway-and petrol stations). Sunday shopping is often separately being offered in various cities. In general shops are open 6 days a week until 8 o'clock pm. On Saturdays shops may have shorter hours of business. The differences are even more considerable if you compare cities and rural areas.
Please be aware of the opening hours of the shops in your vicinity and inform yourself before hand. The opening hours are often quite different.