This sort of clue is included in the French game (8)
I believe the answer is:
lacrosse
'game' is the definition.
(lacrosse is a sport)
'this sort of clue is included in the french' is the wordplay.
'this sort of clue' becomes 'across' (in a crossword).
'is included in' is an insertion indicator.
'the french' becomes 'le' ('the' in French).
'across' placed into 'le' is 'LACROSSE'.
(Other definitions for lacrosse that I've seen before include "Score's uncertain after the Spanish" , "Sport played with sticks" , "Game played with a netted stick" , "Ball game using netted stick" , "Game played with netted sticks" .)