OIP, France.
O.I.P.= Societe Belge d'Optique et d'Instruments de Precision, Ghent, Belgium.
It seems that this is a Francophone maker, but there just may be two separate firms with the same initials. The Ghent works was active about 1939, the following being listed in H&D, and two examples have been reported.
Labor f3.5 50mm This was fitted on a Cinescopie 35mm (1929), also as 45-440mm lenses for portrait work with variable softness for 40°.
Labor f4.5 This was for the same range as the f3.5 for 40°.
Major f4.5 135, 150mm; Triplets for 60°
Major f6.3 90-150mm. Triplets, for 58°
Miror f4.5 50-210mm Q15 type for 58°.
FBB note an O.I.P. wide angle RR f8.0/300mm on a Bertillon Identity camera from 1895.