380 Sellier Bellot?

Can anyone help me to identify the manufacturer?
Round was found in a box of Sellier Bellot, but I doubt the authenticity. I think this was not made in SB. Any idea?
Measurement:
R1 - 10.69
P1 - 9.56
L3 - 25.88
L6 - 35.64
G1 - 9.17
Probably 380 Long.

Thank you