Worse French ruler putting down one former ruler (7)

I believe the answer is:

lousier

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'worse' is the definition.
(I've seen this in another clue)

'french ruler putting down one former ruler' is the wordplay.
I cannot quite understand how this works, but
'ruler' could be 'er' (abbreviation for Elizabeth Regina) and 'er' is found within the answer.
'one' could be 'i' (Roman numeral) and 'i' is found within the answer.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?

I've seen this clue in The Times.

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