It's not a Gitane.
Perhaps something from a very small-output builder, and "40" is the 40th frame he built.
I'm wondering if the forkblades are the classic Reynolds dimensions or the "Continental" dimension...or even if they are not Reynolds but Columbus.
Measure near the forkcrown: long axis and short axis of the oval blade ODs.
Check inside the base of the crown up the steerer (use flashlight) and see if there are any ridges.
The 27.0 seatpost is a bit odd: might be a post just a little too small, but if correct the seat tube could be Columbus SP or Tange or Ishiwata...maybe.