Your turn in Paris to upset foreign character (4)

I believe the answer is:

iota

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'foreign character' is the definition.
(Greek letter)

I cannot understand how the rest of the clue works.

(Other definitions for iota that I've seen before include "The smallest possible amount, or the Greek i" , "Ninth letter of Greek alphabet, small amount" , "A little piece" , "Just a jot, like Greek letter" , "very small part" .)

I've seen this clue in The Times.

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