I don't know if it is because I've had my Brevette return to me, but I am starting to see them more and more... and here is what is interesting... Scandalli made them in seemingly infinite variations and versions. Tthey are identified by their round "flaps" that open when the lever is pushed.
Yours seems to be a 50's-60's version that is either a 3/3 (3 reeds right and left) or a 3/4 (3 reeds right, 4 on the left).
Mine looks similar but is a 4/4 and has more registrations on the right and left hands, but the same traditional round flaps. My uncle recently received a Brevette that is very similar to mine (4/4) but he has no master bar and his bellows clips and shoulder strap mounting points in gold. Quite the variation too!
These accordions, when in good shape are true workhorses, light, reliable and sound nice. The ability to open and close those flaps adds a nice little additional high end when open, kind of like a poor man's sordino. I've noticed one small point... all Brevettes that have the original straps (shoulder AND bass straps), come with black leather top and brown undersides (like yours are).
Mine came new like that but unfortunately, sometime between when it left and came back, someone removed the bass strap and shoulder straps for some unknown reason. I replaced mine with some nice black wide bass and shoulder straps with a good backstrap.
BTW, in your pictures, you have the accordion sitting upside down... no biggie, but just something to know.