Small part of French operation (8)
I believe the answer is:
fraction
'small part' is the definition.
(I've seen this before)
'french operation' is the wordplay.
'french' becomes 'fr' (abbreviation).
'operation' becomes 'action'.
'fr'+'action'='FRACTION'
'of' is the link.
(Other definitions for fraction that I've seen before include "Proportional" , "Small piece forming part of a whole" , "Small proportion" , "little bit" , "Number of mathematicians" .)