Sorry for your loss.
The gun looks like a run of the mill double shotgun pre WWII.
16 Gauge, 65mm, Nitro single proof, dovetailed lumps and extractor. No recognizable name to speak of.
"Medaille d'argent" means silver medal.
Of course nobody would be able to know in which setting this would have been obtained. Could be the county fair.
This marking does not help in any way in assessing a value.
From what I can see, I would say that the gun value maybe anywhere between $250 and $1000.
The only thing unusual is the rounded shape of the back lump, but that does not help much at all either.
Best regards,
WC-
