I had the opportunity to purchase a bike that was similar to yours. The lugs are exactly the same and the dropouts as well. It is a Browning Ten Speed Bike. It is a Belgian made bike with some Japanese parts. The original came with Mafac Racer brakes, a PIVO stem, Simplex front and rear derailleurs, SR crank (Japanese), Shimano hubs (Japanese) hooked on to a Weinman dimpled rim with Simplex spokes, and finally a Stronglight headset. And yes it also has a NERVOR fork. It was a hodge-podge of Asian and French parts. I got mine in its original form and was used by an old lady who left the bike stashed in the garage throughout its lifetime. If you look at the left dropout and scratch the paint you will see a series of numbers... the same way peugeot carbolite frames made in Canada have it. The bike also sports a bracket that is welded on to the left seatstay to connect a reflector. Also the bar that connects the right and left seatstay (where the rearbrake is attached) is a flat piece of stamped steel-not a tube. Now, the search does not end there. Looking for information about the Browning is difficult as well. From what I gathered from the net they came in three models. The one I have seems to be the middle version of it. I also was able to get a copy of the ad of the bike. But the picture is so small that it is difficult to extract the information from it. If you get some info about the bike please share it with me. I myself am still researching on my find. Good luck and God Bless!