Hello,
yes ''f'' or ''ff'' in old french was a ''s'' ''ss''
''fournissent'' is ok !!
Not the perfect answer sorry but just some clues:
Not easy:
Couteliers is the name of the knife maker but too of just a knife dealer...
Idem, boutique is more the name of a shop but it's too a little artisan-craftman shop were we make and sell products...
Note: If they provide four hundred thousand knives per years,
I guess/think the made them and don't just sold them.
( the Amazon of the 18th century
)