Perron symbol means Belgian made.

O in script means 1936 proof. (Prooved under rules adopted 1924).

CHOKE 16.9 means barrel diameter 16.9mm (0.665") 22 cm in front of the breech.

ELG means proved in city of Liege.

PV with lion means powder without smoke, (i.e. smokeless).

16/65 means short chambered 16 gauge; 65mm / 2,1/2" long cases, (not 70mm / 2,3/4").

U star is the countermark of the proof controller.

Wapen Depoten falun import: a Swedish retailer of firearms.

Neumann & Cie in Liege made a very similar looking safety gun, which is perhaps what this is. See photos in the littlegun.be website under "identified craftsmen".