Polish backwater in French Foreign Office? (6)

I believe the answer is:

bureau

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'foreign office?' is the definition.
('office' in French)

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

(Other definitions for bureau that I've seen before include "The ------, familiar name of the FBI" , "Chest of drawers or office" , "The B in the FBI" , "Writing desk with drawers" , "Agency - writing desk" .)

I've seen this clue in The Globe and Mail.

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