Where a standard exists for gaiety? (5)
I believe the answer is:
paris
'where a' is the definition.
The answer is a location as well as being a singular noun. This is suggested by the definition.
'standard exists for gaiety?' is the wordplay.
I cannot quite understand how this works, but
'standard' could be 'par' (standard of play in golf) and 'par' is found in the answer.
'exists' could be 'is' ('be' can be a synonym of 'exist') and 'is' is found within the answer.
This accounts for all the letters.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for paris that I've seen before include "European capital -- Trojan prince" , "City; Juliet's betrothed Count" , "Trojan prince who abducted Helen" , "City where one may see the Mona Lisa" , "where plaster comes from?" .)