Do you know something about this marking?

I brought in a Lefaure shotgun, it has a marking under the barrel that I cannot identify.
Do you have an idea, a lead or a suggestion?

NON. Aucune idée. Trouvée dans aucun livre.
Faites-nous savoir si jamais vous trouvez.

Pas grave, merci d’avoir regardé, je continue mes recherches.

Found this in the Stockel under the name of Malherbe

and this one also sends me back too Malherbe