This information comes from Jack Kissinger, via the Clarinet Bulletin Board at woodwind.org (thread adress listed below).
(I'm happy for this information, but who knows how early Malerne started?! Or did Malerne buy out some other manufacturer?)
Over the years, I've learned a few things about the company [Malerne] that might be helpful to you. Their factory was located in the "woodwind district" outside Paris close to the Buffet and Selmer factories. In addition to manufacturing instruments under their own label, they also manufactured "stencils" for Olds, Conn and Linton (and probably others). According to Jack Linton, current president of Linton, moonlighting was common in that era and district so the company likely had more than a little work done by the same craftsmen who were turning out Buffet and Selmer instruments. Malerne had hopes that one of his children would carry on with the business after him but apparently none were interested so the factory closed and was sold to SML (Strasser, Marigaux and Lemaire) in the 70's or 80's. (I forget the exact date. One can find it on the net if one searches rigorously under Marigaux -- now known for making oboes and especially English horns among the finest in the world.) I suspect (but don't know for sure) that Marigaux clarinets are now made there. Malerne lasted much longer than most of the other "independent" clarinet manufacturers— far past WWII which is when some Klarinet listers seem to think it met its demise.
Malernes probably never achieved the quality of Buffets or Selmers but they are, IMHO, well-built instruments. Nowadays, I would classify my Paris Professional as comparable to a decent intermediate instrument. The "Standard," alas, is probably at best a student model. The "Professional" has four stars in the label. The "Standard" has none. There was also a 3-star model, termed the "Intermediate."
The stars on the professional model are each about an inch in diameter and contain the words, "RM", "Malerne" and "Paris" within them. There is a star on the barrel, another at the top of the upper joint, another at the bottom of the lower joint and a final star on the bell.
So later French Stencil Clarinets in the 50's through 70's are most likely made by Malerne or SML. This site has one review of a Malerne Standard