Sunny city on the French Riviera (4)
I believe the answer is:
nice
I believe this is a double definition.
'sunny' is the first definition.
(nice weather)
'city on the french riviera' is the second definition.
(I've seen this in another clue)
(Other definitions for nice that I've seen before include "Agreeable, kind" , "French resort on the Med" , "Delightful - French resort" , "French resort; pleasing" , "French seaport in SE - sounds pleasant" .)