>My guess would be most likely an early 50s bike (early RH cranks,
>stem, early type undrilled Maxi-Cars, Radios 16) that has gone back
>to RH and possibly had braze-ons cut and modified (would it have
>originally had a Cyclo RD and Herse front changer?) for modern
>derailleurs. And then back again to the RH workshop late 70s for the
>Lily Herse decals.
Indeed, the frame has all the hallmarks of a late 1940s or early 1950s frame. The dropouts are thicker than the mid-1940s frames, yet it has the early-style stem (more rounded) and cranks. Also, the fork offset is generous, more so than on later bikes.
I suspect all the "updating" was done in the 1980s, but probably not by Herse. The front rack originally was for Herse cantilever brakes, and the tab brazed on to clear the Mafac centerpulls isn't typical Herse work. Herse or Desbois probably would have put braze-ons for the Mafac brakes, if the frame was to be repainted anyhow.
Putting it back to 1952 spec wouldn't be hard. You'd need to get a set of Herse cantilever brakes, a Cyclo rear derailleur, and you'd have to make an Herse front derailleur. Some rechroming (fork crown, ends, rear ends), new paint, lettering and lining, and you are done... Might be a worth while project if the bike's your size. It'll probably ride like a dream, if it's anything like the 1950s Rene Herse bikes I have ridden.
Jan Heine Editor Bicycle Quarterly 2116 Western Ave. Seattle WA 98121 http://www.vintagebicyclepress.com