I arrived in Frankfurt about a week ago and have been to Leipzig and Dresden and just arrived in Berlin today. I was searching this site looking for clues about travel documents and real time conditions from people who had traveled recently so I thought I would “pay it forward” with my experiences so far.
CDC card has been checked quite a bit at hotels, restaurants and museums. I took Cameron Hewitts advice and laminated a color copy of it and that has worked fine. I showed my original at the airport but the copy in my pocket has saved lots of trips into my money belt.
German Identification papers were only checked at the airport in Frankfurt and my departure city in Houston (United Airlines). I have not been asked to see that by anyone since I left the airport.
Masks are being worn nearly 100% on all public transportation and inside all buildings. Outside very few people are wearing them.
The Luca app has only been in use once at a church and the guy did not really check it close. I downloaded it and showed him but there were so many other people who did not have the app and he was just having them fill out a paper instead.
So the net-net for me is as long as you have all three important things (passport, CDC card and Germany ID tracking document) you will have no problem at the airport or any hotel, restaurant or museum. I am here for a few more days if anything new occurs I will post an update.