Grippe affected grandma in French city (9)
I believe the answer is:
perpignan
'french city' is the definition.
(I've seen this before)
'grippe affected grandma' is the wordplay.
'affected' indicates an anagram.
'grandma' becomes 'nan' (I've seen this before).
'grippe' with letters rearranged gives 'perpig'.
'perpig'+'nan'='PERPIGNAN'
'in' acts as a link.
(Other definitions for perpignan that I've seen before include "French city" , "French town" .)