Was the company a French subsidiary of Dunlopillo. Considering that Dunlopillo has been around for a while and has a trademark on the name, it seems very likely. Also the "Dunlopillo" typography seems to match.
Perhaps you should ask Dunlopillo about "L'Atelier" and see if the company can tell you something?
Is it solid latex foam?
On the first ad (the one with the old lady), it says that Atelier Dunlopillo was created in collaboration with designer Marc Held and that together they developped a range of 13 models.
There are other ads around without mention of a designer, and indeed one that mentions "création Bernard Govin".
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