On the info on Paul Jaeger, I'd contact Mr. Dietrich Apel as he may have already compiled some info on his uncle. But, but be aware that I don't think them to gee-haw at the time and I don't know that situation was rectified. The reason I mention this is that I seem to recall Mr. Apel being quite blunt on the subject. Anyway, Paul Jaeger seems to have additional sourcing lines to Marholdt Peterlongo, which may have been bi-directional, and some Mauser longarm or component sourcing line. He developed some side-mount optical base as well as a single trigger, I believe. He seems to have been very active in importing from the mid 1950s to the mid 1960s.
Marc may have some info on Masquelier(
http://www.littlegun.be/arme%20belge/artisans%20identifies%20ma/a%20masquelier%20gb.htm ) or I seem to recall a thread on DGS:
http://www.doublegunshop.com/forums/ubbt...=true#Post70653 .
Kind Regards,
Raimey
rse