Nice article supporting high tower (7)
I believe the answer is:
steeple
'tower' is the definition.
(I know that steeple is a type of tower)
'nice article supporting high' is the wordplay.
'nice article' becomes 'le' (definite article in French, so spoken in Nice).
'supporting' means one lot of letters go next to another (in a down clue, some letters go below others).
'high' becomes 'steep' (similar in meaning).
'le' after 'steep' is 'STEEPLE'.
(Other definitions for steeple that I've seen before include "point" , "part of church" , "Tall building" , "Jack up this?" , "Pointed structure" .)