Fish and French hound (6)
I believe the answer is:
basset
'hound' is the definition.
(basset hound is an example)
'fish and french' is the wordplay.
'fish' becomes 'bass' (bass is a kind of fish).
'and french' becomes 'et' ('and' in French).
'bass'+'et'='BASSET'
(Other definitions for basset that I've seen before include "GAME" , "Short-legged hound that hunts hares" , "Low-set hound" , "Type of hound" , "Low, smooth-haired breed of hound" .)