Cleaner meets the King in French and Belgian city (9)
I believe the answer is:
charleroi
'belgian city' is the definition.
(I've seen this before)
'cleaner meets the king in french and' is the wordplay.
'cleaner' becomes 'char' (char can mean a cleaner).
'meets' means one lot of letters go next to another.
'the king' becomes 'R' (abbreviation for rex, king in Latin).
'in' is an insertion indicator.
'french and' becomes 'leoi' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'r' placed within 'leoi' is 'leroi'.
'char'+'leroi'='CHARLEROI'
Can you help me to learn more?
(Other definitions for charleroi that I've seen before include "Belgian city" , "Belgian place" , "somewhere near Brussels" , "European location" , "in Belgium" .)