French M51 Rucksack

I started searching for a WWII French rucksack as I realized I didn't have one and found this instead. What's hilarious is they are trying to sell these for anywhere from $200-$500 on eBay as WWII French rucksacks which they are not. I snagged this for $41.00 which is a good price for one in this condition.

There apparently are similar rucksacks from WWII which were mountain packs then using a very similar steel frame to the US Mountain Packs from the same time period. Then a M47 model after the war which changed the frame and then this in 1951. Most French soldiers had a small squarish pack similar to the British ones from pre WWI through WWII using different materials. Not many of them around either.

Information on French rucksacks is nearly non-existent, at least in English and it took me two days to figure out what this is and I'm still not positive on the year of manufacture as there was a shift from tan and brown leather to green with grey leather at some point. What's even more confusing is these same packs were sold on the civilian market with only slight variations in style. Pretty sure this one is military issue. The white square is where the soldiers typically put their personal information. Civilian versions lack this and typically have a cloth manufacturers tag.

It is a confusing mess however. I'd like to learn more about them so I can get the other models eventually.

Pretty sure this would not be an early one but a little later, still appropriate for the Indochina and Algerian wars. It also appears to be unissued with light dirt and rust from storage. It's complete with it's two extra straps. Made by Lafuma, at least the frame is. Can't read the bag manufacturer, I've read there are several but the frames are all Lafuma.

https://www.milsurps.com/images/impo.../ykcTTLy-1.jpg

https://www.milsurps.com/images/impo.../IAs15Fc-1.jpg

https://www.milsurps.com/images/impo.../Tfbp9Xh-1.jpg

https://www.milsurps.com/images/impo.../Vghi3Ox-1.jpg

Looks like the US M42 somewhat...

Yes, they are similar and the earlier French models have the frame like the M42. It's possible the French model came first as the M40 but on this I'm not sure. And to top it all off, I think they are all based on the British bergam rucksack.