Just returning today. We were in the Skyline bar at the Marvel hotel last night with our DDs 20 and 18. Our DD 18 ordered a drink, and they asked for her ID, even though we were both with her. No problem. We had her DL with us (passports were in the room safe), and gave it to them. Her birthday is 12 September, so she turned 18 a few months ago. The server returned and said she can’t serve her the drink since she is not 18. I said she is 18, just turned 18 in September. She went to speak to the manager, and they again said she was not 18. I pointed out that the dates on our DL’s from Texas are written DD/MM/YYYY, not MM/DD/YYYY like in Europe. To them, it looked like her birthday was December 9 instead of September 12. Ultimately, the manager came over, and he spoke better English (and my French is decent but apparently not good enough to communicate this concept of writing the date), and he understood and was very nice about it. We showed them my other DD’s DL (her birthdate is 22nd), so that they could see how the date convention worked in the US. They were super nice about it, but strictly enforcing the rules, which we didn’t have a problem with.
In any case, this is just to say that even with both parents with her, they were very strict about her being 18 to have alcohol. YMMV!
That said, we were primarily in Europe to visit our DD20 who has been studying abroad in Berlin since August. When we were in Berlin, she was never asked to show ID to order wine/alcohol at any bar or restaurant when she was with us.