Warm reddish-brown colour new in Italian walled city (6)
I believe the answer is:
sienna
'warm reddish-brown colour' is the definition.
'sienna' can be an answer for 'colour' (I've seen this before). I am not certain of the 'warm reddish-brown' bit.
'new in italian walled city' is the wordplay.
I cannot really see how this works, but
'new' could be 'n' (common abbreviation eg NT for New Testament) and 'n' is located in the answer.
'italian' could be 'i' (abbreviation for Italian) and 'i' is present in the answer.
The remaining letters 'sena' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for sienna that I've seen before include "Type of earth used as pigment" , "Brownish-yellow substance used as pigment" , "Yellow-brown clay used in paint pigments" , "colouring" , "A shade" .)