Commonwealth citizen is French too (and English) (6)
I believe the answer is:
aussie
'commonwealth citizen' is the definition.
(short for Australian)
'french too and english' is the wordplay.
'french too' becomes 'aussi' ('too' in French).
'and' says to put letters next to each other.
'english' becomes 'e' (abbreviation).
'aussi'+'e'='AUSSIE'
'is' acts as a link.
(Other definitions for aussie that I've seen before include "Someone from Sydney? (slang)" , "Adelaide native?" , "Native of Canberra (colloq.)" , "inhabitant of Brisbane" , "Australian (colloq.)" .)