Scented mixture first brought back for French king and emperor (9)
I believe the answer is:
potpourri
'scented mixture' is the definition.
(mixture with a nice smell)
'first brought back for french king and emperor' is the wordplay.
'first' becomes 'top' (synonyms).
'brought back' says the letters should be written in reverse.
'for french' becomes 'pour' ('for' in French).
'king and emperor' becomes 'RI' (Rex Imperator, imperial term for king and emperor).
'top' written backwards gives 'pot'.
'pot'+'pour'+'ri'='POTPOURRI'
(Other definitions for potpourri that I've seen before include "Perfuming mixture" , "fragrant blend" , "Mixture of dried, scented items" , "assortment of botanical stuff?" , "hodgepodge" .)