One European has good first smell (5)
I believe the answer is:
greek
'one european' is the definition.
(Greek is an example)
'good first smell' is the wordplay.
'good first' becomes 'g' (1st letter of 'good').
'smell' becomes 'reek' (reek is a kind of smell).
'g'+'reek'='GREEK'
'has' acts as a link.
(Other definitions for greek that I've seen before include "Person from Athens" , "Hellenic" , "Foreigner" , "National?" , "(All) incomprehensible (to me)" .)