Has some nerve destroying half the city belonging to the French (6)

I believe the answer is:

gallic

I'm a little stuck... Click here to teach me more about this clue!

'french' is the definition.
(I know that french can be written as Gallic)

I don't understand how the rest of the clue works.

Can you help me to learn more?

(Other definitions for gallic that I've seen before include "Typically French or of France" , "Characteristic of the French" , "Pertaining to France" , "Of the French/France" , "Like certain wars" .)

I've seen this clue in The Irish Times.

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