This is a cruciform - 4-edged - blade that is nothing more than a "pig-sticker". It was manufactured to fit the French Model 1886 Lebel Infantry Rifle and saw action in WWI and WWII in various configurations. The original model was ~25" in overall length, while this one has been shortened to ~18" overall. They have a hooked "blade-breaker" quillon and silver-alloy (white metal) grip/hilt. This variant is also different from the original in that it employs a removeable handle to allow for blade replacement (the blades were very fragile); the original was permanently fixed.
The bayonets were eventually intended to be replaced by the French Model 1892 Mannlicher-Berthier Bayonet (and infantry rifle).
The scabbard is tubular in shape, with rounded tip (no finial).