Circus performer of note entertaining the French (4)
I believe the answer is:
flea
'circus performer' is the definition.
(as in a flea circus)
'note entertaining the french' is the wordplay.
'note' becomes 'fa' (fourth note in sol-fa notation: doh, ray, me...).
'entertaining' indicates putting letters inside.
'the french' becomes 'le' ('the' in French).
'fa' going around 'le' is 'FLEA'.
'of' acts as a link.
(Other definitions for flea that I've seen before include "beastie?" , "Biting type" , "one is proverbially fit" , "Jumping parasite" , "Leaping insect" .)