Water, in Paris (3)
I believe the answer is:
eau
'water in paris' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for eau that I've seen before include "Quick to notice things" , "-- de vie" , "Popular toilet water - . . . de Cologne" , "Water in France" , "French water, may be Cologne" .)