Mole maybe from Flanders to swap France with Belgium (7)
I believe the answer is:
blemish
'mole maybe' is the definition.
I don't understand the rest of the clue.
(Other definitions for blemish that I've seen before include "acne?" , "deformity" , "Flaw that spoils a thing's perfection" , "Flaw; moral defect" , "Small flaw" .)