A tenant as the French understand (6)
I believe the answer is:
lessee
'a tenant' is the definition.
(lessee is a kind of tenant)
'the french understand' is the wordplay.
'the french' becomes 'les' (plural form of 'the' in French).
'understand' becomes 'see' (synonyms).
'les'+'see'='LESSEE'
'as' is the link.
(Other definitions for lessee that I've seen before include "Who pays the rent" , "One holding lease on property" , "One who rents" , "Tenant who holds a lease" , "Person who rents" .)