The French included in balanced side (6)
I believe the answer is:
eleven
'side' is the definition.
(I've seen this before)
'the french included in balanced' is the wordplay.
'the french' becomes 'le' ('the' in French).
'included in' means one lot of letters goes inside another.
'balanced' becomes 'even' (I've seen this in another clue).
'le' put inside 'even' is 'ELEVEN'.
(Other definitions for eleven that I've seen before include "XI as Roman numeral" , "Number killed in the Peterloo massacre" , "Time for the mid-morning tea break?" , "Late" , "Cardinal" .)