Income from flat in Parisian street (7)
I believe the answer is:
revenue
'income' is the definition.
(revenue is a kind of income)
'flat in parisian street' is the wordplay.
'flat' becomes 'even' ('even' can be similar in meaning to 'flat').
'in' is an insertion indicator.
'parisian street' becomes 'rue'.
'even' put within 'rue' is 'REVENUE'.
'from' acts as a link.
(Other definitions for revenue that I've seen before include "Tax for the government" , "Government's income" , "Income from tax" , "Money received" , "Return" .)