FWIW, I just checked the website of FRA airport at
http://www.frankfurt-airport.com/con...s/lounges.html
and this is what shows under Sakura Lounge :
Japan Airlines Sakura Lounge
Daily from 5:30 a.m. to 11:30 p.m.
+49-69-690 72716
First Class PASSENGERS of Japan Airlines; holders of the Japan Global Card; holders of the JGP Card; passengers with Lounge invitation card
Terminal 2, Level 3, after the security checkpoint, near gate D8