Catholic state supported by us in Paris, like Notre Dame (9)
I believe the answer is:
cavernous
'like notre dame' is the definition.
I can't tell whether this defines the answer.
'catholic state supported by us in paris' is the wordplay.
'catholic' becomes 'C' (abbreviation as in RC for Roman Catholic).
'state' becomes 'aver' (both can mean to declare).
'supported by' is a charade indicator (letters next to each other) (in a down clue, some letters hold up others).
'us in paris' becomes 'nous' (I've seen this in another clue).
'c'+'aver'+'nous'='CAVERNOUS'
Can you help me to learn more?
(Other definitions for cavernous that I've seen before include "Gaping" , "of large underground chambers" , "like a big pit" , "Roomy" .)