That logo was started around 1965, and they changed to the sans serif logo (look at my avatar) in 1974. I have seen magazine ads from late 1974 with the sans serif.This blade looks like it could be as late as the mid-1970´s. It has the pre-1976/7 logo, but is the same dark blue package color as the mid-70´s blue blade in the US. Note that in the US, at the time, these blades had PTFE coatings (as evidenced by the patent on this blade with same packaging color https://www.mr-razor.com/Rasierklingen/1974 (U1) Blue Blade.jpg ). If these blades have the coating, they are incredibly good, and have decent longevity (5-7 shaves for me). I would try one.
Gillette France did a lot with carbon steel blades with PTFE coatings. Gillette had patents to better adhere the PTFE to non-stainless blades, and they can be wonderful shavers.
Also, If you could take pictures of the blade when you try it and put on this thread, it would add to the knowledge base here, and I would appreciate it.