Gentlemen,
I bought this shotgun by chance when it had just been put online on a sales site. Poorly photographed, poorly described, I risked and was lucky.
It's a big shotgun, massive, marked "Lefaucheux breveté", "10 rue de la bourse à Paris", and "Arquebusier ordinaire de Monseigneur le Duc de Nemours". Dated 1845, rather surprising because at that time one might think that Casimir Lefaucheux manufactured his famous breechloading pinfire shotguns.

It needs a restoration, but I consider it in good condition, I am sure it will become like new again. The real good surprise is that it’s a 10 gauge, which might explain why it’s a Lefaucheux... a special order to go duck hunting?
The Duke of Nemours (1814-1896) is the son of King Louis-Philippe, here he is in 1852:

Note that this address "10 rue de la bourse", will be where Eugène Lefaucheux settled in 1850.
This is what it currently looks like:

I will give you news in a few months, when it has been restored.
I can’t wait to bring him to the hare hunt next year!