Becoming number one in France — this requires capital (6,4)

I believe the answer is:

proper noun

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'france this requires capital' is the definition.
The definition suggests a singular noun which matches the answer.

'becoming number one' is the wordplay.
'becoming' becomes 'proper' ('proper' can be similar in meaning to 'becoming').
'number' becomes 'no' (abbreviation for 'number').
'one' becomes 'un' (I've seen this in other clues).
'proper'+'no'+'un'='PROPER NOUN'

'in' acts as a link.

Can you help me to learn more?

(Another definition for proper noun that I've seen is " James for instance".)

I've seen this clue in The Times.

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