Tot enters the French arena, running (9)

I believe the answer is:

laddering

'running' is the definition.
('ladder' can be a synonym of 'run')

'tot enters the french arena' is the wordplay.
'tot' becomes 'add' ('add' can be a synonym of 'tot').
'enters' is an insertion indicator.
'the french' becomes 'le'.
'arena' becomes 'ring' (I've seen this in other clues).
'add' placed inside 'le' is 'ladde'.
'ladde'+'ring'='LADDERING'

(Another definition for laddering that I've seen is " Running".)

I've seen this clue in The Times.

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