Ihad the luck to get a fine Dumoulin round action sidelock gun from Liège maker F. Dumoulin & Cie. What I find especially remarkable is the year of proof: 1943 ! That was in the midst of WW II, Belgium was occupied by the Germans and the production of fine guns probably was down. Nevertheless this gun is a nice example of Liège artisans. See more:

http://www.hunting-heritage.com/blog/index.php/2018/04/04/dumoulin-round-action-sidelock/

Cheers,
Gunwolf