Grain obtained from ridge over river in French city (5,4)
I believe the answer is:
brown rice
'grain' is the definition.
(brown rice is a kind of grain)
'ridge over river in french city' is the wordplay.
'ridge' becomes 'brow' (I can't justify this - if you can you should believe this answer much more).
'over' is a charade indicator (letters next to each other) (in a down clue, some letters go over others).
'river' becomes 'r' (abbreviation).
'in' is an insertion indicator.
'french city' becomes 'nice' (Nice is a French city).
'r' put into 'nice' is 'nrice'.
'brow'+'nrice'='BROWN RICE'
'obtained from' acts as a link.
Can you help me to learn more?
(Other definitions for brown rice that I've seen before include "Unpolished food grains" , "Health food" , "Dark grains" .)