Trickery of the French in a sense (7)
I believe the answer is:
sleight
'trickery' is the definition.
(as in sleight of hand)
'the french in a sense' is the wordplay.
'the french' becomes 'le' ('the' in French).
'in' indicates putting letters inside.
'a sense' becomes 'sight' (sight or vision is a sense).
'le' going within 'sight' is 'SLEIGHT'.
'of' is the link.
(Other definitions for sleight that I've seen before include "Dexterity (usually of hand)" , "Artful trick" , "distraction?" , "craft" , "Manual dexterity" .)