Laid up the French cutters (7)
I believe the answer is:
sickles
'cutters' is the definition.
(sickle is a kind of cutter)
'laid up the french' is the wordplay.
'laid up' becomes 'sick' ('sick' can be similar in meaning to 'laid up').
'the french' becomes 'les' (les is the in french).
'sick'+'les'='SICKLES'
(Other definitions for sickles that I've seen before include "Curved short-handled blades" , "cutting implements!" .)