Originally Posted by
Kiwi Flyer
AFAIK the AC lounge is in the nonschengen zone. Personally I wouldn't go through immigration twice, and probably an extra security check, to visit a lounge (unless that lounge was the FCT and even then I'd hesitate).
I would perhaps not go through security and passport control, not sure.
Looking back, I have on occasion gone through passport control twice at FRA, but not through security. I don't recall why, possibly to go to a lounge, or to something that happened to be past passport control.
I have also on occasion gone through an extra security at some places in the US where the only lounge was at different gates. BOS for expample.