The key to identifying the difference between a VC "Helice" top-lever action (note: VC never copywrited the word "Helice") and ones simply labeled "Helice" is on the top lever. VC reversed the screw shaft joining the lever so no screw head visible. It would help of you'd post the barrel flats and the advertising on the lower sections of the barrel, along with the water-table/action flats.
Here are some used "Solyd"'s 'for sale in France - looks like it's a Saint-Etienne made gun:
https://armurerie-bernizan.com/inde...sil-de-chasse-fusil-de-chasse-cal-12-65/http://www.aiolfi.com/vente/686-arm...hasse-solid-categorie-c/#tab_descriptionhttps://www.naturabuy.fr/Saint-Etienne-solyd-item-9811951.htmlhttps://www.chassepassion.net/forums-chasse/topic/recherche-dinfos-sur-un-fusil-juxtapose-cal-16/In the last 2011 article on Passion la Chaise,
. . .-- the author identifies the barrel maker as "Fanget" and one correspondent believe it was made by VC because of the trademark "Acier Diamont" (diamond steel).
. . .-- But another claimed it is "artisanal made" in Saint-Etienne."
. . .-- One said a call to this armurier in Saint-Etienne could solve the mystery: un armurier devrait pouvoir te rensseigner: cedric camus 04 77 56 72 46.
. . .-- The poster said his father's "Solyd" was bought in the 1950's.
. . .-- Later on in the post, a poster put up another "Solyd" and said it was made by Manufrance (post no longer available):
http://www.naturabuy.fr/Veritable-Hammerless-Saint-Etienne-modele-Solyd-item-235036.html. . .-- (The article also discusses the word "hammerless" which is of course English).