I tried this last Friday at a participating pharmacy in a small town in southeastern Bavaria. I had just arrived that day and needed to go into town anyway so I thought I'd give it a quick try before the stores were closing without worrying too much about the outcome. I provided my CDC card and passport. The lady working in the front took both documents and said she'd have to check with the owner/boss who'd make the decision on whether to accept the CDC card as sufficient proof of vaccination. After a few minutes she came back, apologized, and said he'd told her that they'd only accept documents issued in other EU countries, not the US. I'm sure that I could have either pressed my case or tried other pharmacies and eventually been successful, but I didn't want to spend any more time on this during my short trip. I'll probably try again during a longer trip in August, though the only time I needed to show proof of vaccination during this past trip was to check into a hotel, and the CDC card was readily accepted for that.