All About Pocket Knives

I found this interesting knife at an Antiques Fair; the seller said it had come with a WW2 British Officers estate. I believe it is French, with INOX one side of the minimal ricasso and Bte ***** on the other. It's a little worn and doesn't close completely, but the spring mech works fine.
It's 8 1/2" overall, with a 4" blade.
Is it old enough to be 1940's ?

WOW! Neat old knife! I would agree that it is French due to the use of screws to hold it together. I have a couple of old French sailor's knives that feature screws for the blade pivot. The number looks like it might be a French patent number;probably for the release mechanism.

surely French because the stamp on the blade "BTe S..." means " BTe SGDG" ie " Breveté Sans Garantie Du Gouvernement" (Brevet = Patent)
what i can say with this information is that this knife has been made beetween 1844 (beginning of this kind of stamping) and 1968 (ending of this stamping)
never seen this model

stancaiman wrote:surely French because the stamp on the blade "BTe S..." means " BTe SGDG" ie " Breveté Sans Garantie Du Gouvernement" (Brevet = Patent)
what i can say with this information is that this knife has been made beetween 1844 (beginning of this kind of stamping) and 1968 (ending of this stamping)
never seen this model

Stancaiman! Glad to see you posting again ;it's been awhile. Always glad to see your input.

thank knife7knut

Thanks for the info guys, much appreciated.

you're welcome, if you have the complete patent number you can try to find it in the european patent database : https://worldwide.espacenet.com/?locale=fr_ep

i'm curious of this knive, is it a automatic or just a level to unlock the blade ?
the shape look like modern "navette" knives ( see ISARINOX knive or BEGON knive or Douris Chastel knive for example )
but the majority of them have more than one blade.

This is an automatic knife, with a leaf spring in the recess for the blade.
There is a number on the blade, but it doesn't seem to flag up anything relative on the Patent site; 624.473

i don't find this ref in the databases
i think it's a "DOURIS CHASTEL" (see at the bottom of this link https://www.lecouteau.info/technique-te ... atiques-1/ )
DOURIS CHASTEL is "born" in 1942 but it's can be right with what you write at the beginning of this post

Many thanks, brilliant job of finding my knife, STANCAIMAN! Douris Chastel it is! It's good to hear that the story of my knife being a WW2 'bringback' could be right!
I have another French knife, that has been in my family for over 100 years (allegedly) so I'll do a new post for that one and see if you can confirm its age.