give it a try with the google translator
"Rare French hunting rifle of "Devisme patented in Paris" with flint and percussion, one shot, caliber 17.5 mm. Strong barrel patinated, striped, round, with thunder pans, signed on the tape "Devisme Patented in Paris". Platinum front signed and flat dog. Very rare system of firing, both flint and percussion, certainly a private order around 1840. Trim chiselled iron. Crosse was short, partly walnut checkered and enhanced with gold nails. Original iron rod and nickel silver on the tip to protect the scratches. Alas it misses this original rise to slip. Length: 118 cm Barrel length: 79,1 cm Very good condition! Around 1840. Louis-François, Alexis and Fabrique DEVISME: founded in 1834. Numerous French and Belgian patents, 1854-1860. Exhibition of Paris in 1839 I remain at your disposal for all other information ..." make sense

the combination of percussion and flint look make its very unique! can't remember such a system before

the checkering combined with nails was ala mode in the early 1830s

here on a very early Dreyse needle fire double gun