Liberia: One time famous French brand, who supposedly, “In the early 1980s, Liberia was the first French company to manufacture mountain bikes, which it even exported to the United States. ” See:
velovintageagogo. Which would place it ⇐ 1982, as
Peugeot came out in 1982 and Motebecane sold it's Mt. Becane in 1984. The attached pic, house branded a Burdet but was made by Liberia. Note that this has a derailleur paired with an internal hub (how?) giving it 6x3x3=54 speeds (!) using a 1984 Sachs-Huret Rider type 2. So perhaps its not that old?
velovintageagogo