Reportedly genuine item that circulated in Paris (5)
I believe the answer is:
franc
'item that circulated in paris' is the definition.
(former French currency)
'reportedly genuine' is the wordplay.
'reportedly' indicates a 'sounds like' (homophone) clue.
'genuine' becomes 'frank' (synonyms).
'frank' is a homophone of 'FRANC'.
(Other definitions for franc that I've seen before include "Old French currency" , "Old French money" , "Nonsense (colloq.)" , "Former French monetary unit" , "Historic currency" .)