Yes this is a seriously weird setup! As yebbut has told us, the year is 1946-47 (although they would have all been called "1947 models" - FN called them "Series XIII", introduced in September 1946) and this one is the 250cc OHV. Guy de Becker's book on FN has a technical article about the front fork, which details why it is so superior to others in smoothing out the ride. If you look at it, it is basically a swinging arm pivotted out in front of the wheel.
Yebbut - it was smooth but did it steer? I'm not sure what killed off the design so quickly, but let's guess steering, or perhaps the consequences of shearing the bolts that held the massive cantilever to the steering head!
Leon