A drawing of French symbol (6)
I believe the answer is:
design
'a drawing' is the definition.
(I know that design is a type of sketch)
'of french symbol' is the wordplay.
'of french' becomes 'de' ('of' in French).
'symbol' becomes 'sign' (I've seen this before).
'de'+'sign'='DESIGN'
(Other definitions for design that I've seen before include "Develop or prepare a plan" , "End" , "Bluepriint, pattern" , "Blueprint, pattern" , "project" .)