Sign name in Spanish city (4)
I believe the answer is:
leon
'spanish city' is the definition.
(I've seen this in other clues)
'sign name' is the wordplay.
'sign' becomes 'leo' (star sign).
'name' becomes 'n' (common abbreviation e.g. on forms).
'leo'+'n'='LEON'
'in' is the link.
(Other definitions for leon that I've seen before include "Put up Chrissie" , "- Trotsky, communist" .)