Declare area good in street in Paris (5)
I believe the answer is:
argue
'declare' is the definition.
(thesaurus)
'area good in street in paris' is the wordplay.
'area' becomes 'a' (maths abbreviation).
'good' becomes 'g' (abbreviation).
'in' means one lot of letters goes inside another.
'street in paris' becomes 'rue'.
'g' put within 'rue' is 'rgue'.
'a'+'rgue'='ARGUE'
(Other definitions for argue that I've seen before include "Bandy words" , "Make a case" , "Quarrel or disagree" , "Discuss, contend" , "Debate, contend" .)