This is Villa Drusch, designed by Claude Parent, the famous French modernist built in 1963 for a local industrialist Gaston Drusch. It implemented the “theory of oblique architecture” because it looks like a house architect turned on its side.
Living space is encased in an aluminum-framed glass, which naturally opens the interior lights. A staircase inside the exterior structure following the slope. Many of the inner surface is also made of concrete.
It’s amazing, though the house was designed a long time even today look more contemporary.