Where Riviera tourists may go, wanting energy boost (5)

I believe the answer is:

tonic

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'boost' is the definition.
(tonic can mean a stimulant or booster)

I don't understand the remainder of the clue.

(Other definitions for tonic that I've seen before include "Producing tension of muscles" , "do for musicians" , "Stimulant" , "__water; gin mixer" , "fizz" .)

I've seen this clue in The Times.

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