Ditties of French boys after one quits series (8)

I believe the answer is:

chansons

'ditties of french' is the definition.
(a chanson is a French song or ditty)

'boys after one quits series' is the wordplay.
'boys' becomes 'sons' ('son' can be a synonym of 'boy').
'after' means one lot of letters go next to another.
'one quits series' becomes 'chan' (I can't explain this - if you can you should give a lot more credence to this answer).
'sons' put after 'chan' is 'CHANSONS'.

I've seen this clue in The Guardian.

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