European city that never sleeps? Not quite (6)
I believe the answer is:
naples
'european city' is the definition.
(I've seen this before)
I can't explain the remainder of the clue.
(Other definitions for naples that I've seen before include "Port near to Vesuvius" , "City near Mt. Vesuvius" , "See it and die, they say" , "Italian city of the planes" , "Planes (anag) - somewhere in Italy" .)