Reversed a limit on the French mammal (6)
I believe the answer is:
alpaca
'mammal' is the definition.
(alpaca is a kind of mammal)
'reversed a limit on the french' is the wordplay.
'reversed' says the letters should be written backwards.
'limit' becomes 'cap' (capping is a kind of limiting).
'on' says to put letters next to each other.
'the french' becomes 'la' ('the' in French).
'a'+'cap'+'la'='acapla'
'acapla' backwards is 'ALPACA'.
(Other definitions for alpaca that I've seen before include "S American mammal in the llama family" , "Llama-like domesticated animal, valued for its wool" , "Cloth made from wool of S American llama" , "Wool-yielding camelid" , "Fabric from wool of S American llama" .)