John supporting France and our ambience (7)
I believe the answer is:
flavour
'ambience' is the definition.
(I know that flavour is a type of ambience)
'john supporting france and our' is the wordplay.
'john' becomes 'lav' (both can mean a toilet).
'supporting' is a charade indicator (letters next to each other) (in a down clue, some letters go below others).
'france' becomes 'f'.
'and' means one lot of letters go next to another.
'lav' after 'f' is 'flav'.
'flav'+'our'='FLAVOUR'
(Other definitions for flavour that I've seen before include "essential quality" , "Season" , "Relish" , "Distinctive taste" , "property" .)