I would say that it is probably possible to live in Berlin without bringing too much plastic into your home. It only requires a lot of time, money, and constant vigilance. The minute you stop paying attention, you find yourself with some new bits of plastic in your possession.
You also would have to be willing to forego a lot of things. In our case, the things we noticed you can't really get without plastic included chicken, snickers bars, gummy bears, and frozen pizza.
The farmer's market is a great place to go to avoid plastic. I even found insoles! Kaufhof Galeria is the worst place. Yesterday, we went there to get Vigo a new pair of rain boots. We completely forgot about Plastic Avoidance Week and we walked out of there with three new plastic bags.
Even when you try to buy your soda or water in a glass bottle, you end up with some bits of plastic on the edge of the metal lid. At least beer is safe. The best way to avoid bringing more plastic into the house is simply not to buy anything, which is actually not such a bad solution.
My friend Susan sent me this video. Enjoy!