[oneounceload]

FWIW, w/o a trip to France, AND a talk with older/knowledgeable gun people there, that may be an insurmountable task - since the reason guns like these were unmarked by a maker is that they actually had no single maker.
These type guns, referred to as "guild guns" today, were each made by several different entities (people/families/small partnerships/etc) - one of which was most likely an expert barrel maker, another an action maker/actioneer, and yet another a stockmaker.

All the "marks" are the legal marks required in Europe's various countries (France in this case), to both "prove" that the gun was made well enough to fire/use, in some case what it was made of, and to explain what ammo it took in the event that somebody who happened across one didn't know.


[ and maybe a rough estimate as to its value.]

Guild guns, some very ornate indeed, generally have low collector attraction, with most of their value lying in their utility - which should always be verified by a competant gunsmith prior to use.

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Always interesting because many of the English "BEST" guns were made the same way - a lone soul in one hamlet made locks, another the action, another the stock, etc..........and then they were "finished" by the name brand house and sold as such - yet THOSE guns have HUGE collector value......