A Parisian on leave with journalist has not returned (10)
I believe the answer is:
unrequited
'not returned' is the definition.
(I've seen this before)
'a parisian on leave with journalist' is the wordplay.
'a parisian' becomes 'un'.
'on' says to put letters next to each other.
'leave' becomes 'requit' (I can't explain this - if you can you should give a lot more credence to this answer).
'with' is a charade indicator (letters next to each other).
'journalist' becomes 'ed' (short for editor).
'un'+'requit'+'ed'='UNREQUITED'
'has' acts as a link.
Can you help me to learn more?
(Other definitions for unrequited that I've seen before include "(Love) not returned" , "Strong emotion that's not reciprocated" .)