So much for my mis-matched fork theory. Given that seat post it's not French, probably not Swiss (that was one place I might have guessed due to the pointy stay ends), still could be Austrian (didn't know KTM ever made bicycles, but guess they did) though doesn't look like typical Austrian brands we see: A-D, Puch, Steyr, Capo...and I wouldn't rule out British or even Dutch. Any markings on either BB cup? how about just the width of the shell: either 68mm or 70mm (so your measurement has to that accurate).