Villain shot up in Parisian street (5)
I believe the answer is:
rogue
'villain' is the definition.
(rogue is a kind of villain)
'shot up in parisian street' is the wordplay.
'shot' becomes 'go' (I've seen this in other clues**).
'up' says the letters should be written in reverse (in down clue: letters go upwards).
'in' is an insertion indicator.
'parisian street' becomes 'rue'.
'go' reversed gives 'og'.
'og' going inside 'rue' is 'ROGUE'.
(Other definitions for rogue that I've seen before include "Scamp" , "Chap in gallery" , "Fraud" , "Mischievous person" , "Old Greek" .)