Put grandma up in French city (6)
I believe the answer is:
nantes
'french city' is the definition.
(Nantes is a city in France)
'put grandma up' is the wordplay.
'put' becomes 'set' (both can mean to place or position).
'grandma' becomes 'nan' (I've seen this before).
'up' says the letters should be written in reverse (in down clue: letters go upwards).
'set'+'nan'='setnan'
'setnan' in reverse letter order is 'NANTES'.
'in' is the link.
(Other definitions for nantes that I've seen before include "French FC" , "Port city in western France" , "City and port of W. France on the Loire" , "port abroad" , "Loire port; an old Edict" .)