made from a old bayonet.
I believe this is a re-tooled French Bayonet...WWI Era or a bit earlier...
I'd say earlier than WWI. Probably 1850's or 1860's perhaps grip originally for a British Brunswick bayonet. But, it's been modified, the hollow parts of the grip that held the locking clip appear to be filled with lead and I think the blade has originated not from a bayonet but from a twin edged short sword from same era such as the British "Drummers sword", sometimes called a Bugler's sword. Is it a Civil war knock up? Maybe.
Actually I think I can see what's happened. It is a Brunswick bayonet. The blade had been cut in half and the bottom section which is double edged, has been reattached (rather crudely) to the hilt.