BERLIN—Amazon says it plans to cut the use of plastic packaging in Germany following complaints that the online retailer is contributing to growing mountains of waste. The company said Monday that its German logistics center will replace all single-use plastic packages with paper-based bags or cardboard boxes by the end of the year. Exceptions are possible when third-party sellers provide products in packaging that can be relabeled for delivery, and when couriers are asked to leave products in outdoor locations during rainfall, the company said. Environmental groups in Germany have long urged Amazon, as one of the biggest online retailers, to lead the way in reducing unnecessary waste.