I missed the very first post that said "Chevalier" "A Paris" (left barrel).
Well, that does it as far as location.
It turns out that when E. Lefaucheux closed down in 1881, he was succeeded by "Chevalier et Dru". Apparently Chevalier closed down in 1889.
That seems quite ancient for a Greener bolted boxlock, but that would explain the lack of barrel weight.
On the other hand the 16 C in a rhombus appeared in 1898. So I am still confused....
WC-