Cups from subtropics in nice restaurant (6)

I believe the answer is:

bistro

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'restaurant' is the definition.
(I know that bistro is a type of restaurant)

I can't explain the remainder of the clue.

Can you help me to learn more?

(Other definitions for bistro that I've seen before include "Small informal French cafi" , "'Small, inexpensive restaurant (6)'" , "Coming out of restaurant" , "Modest restaurant" , "Cafe/restaurant" .)

I've seen this clue in the Irish Times (Crosaire) and The Irish Times.

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