It‘s french

 

Think a few were made for the French navy, overseas use, but in the main they adopted the Kropatschek rifle/bayonet.
Trust Andy comes up with a solution.

 

With only two pictures, hard to be 100% sure.
First thing, and the only sure : not for Navy, but for Navy Infantry.
The Navy was using the Chassepot… and later model 1878 Kropatschek… the handle of the bayonet for this late model has a specific straight back.
So, It could be a bayonet for :

• model 1874 rifle
• model 1884 rifle
• model 1885 (and 74/85) rifle.

It is possible to make difference between the three models on details not visible on your pictures.
It is tricky to make difference between those for model 1884 and 1885, but easy to know if it is made for model 1874. Make an extra picture of the back of the handle of your bayonet. And also of the locking button on the left side.