I get what you mean Lu
The Proust chair was the result of Mendini's 're-design'. By taking familiar furniture objects and then transforming them by adding colour and patterns to them, Mendini changed the whole character of these objects.
For example, this is Mendini's 1978 re-design of Marcel Breuer's famous 'Wassily" chair from 1925. By adding decorations to it, the whole context of this object is changed.
This chest of drawers is re-designed with decorations in the style of a Kandinsky painting.
These objects were created with an avant-garde Milanese design group called Studio Alchimia -- they were not intended for production and are now important examples of late twentieth century design theory. Some are now being reproduced by Italian furniture makers for regular home decoration.
However, the newer versions are not as radical as the originals ....they have been toned-down to make them more 'tasteful' for the general consumer market.
For example, Mendini designed a production version of the chest of drawers above for the Manufacturer Zanotta.

That Zanotta chest of drawers is in this interior you posted (bottom right)
This is an original Proust chair from 1978 produced by Studio Alchimia;
-and this is a recent reproduction of the Proust chair being made by the Italian manufacturer Cappellini.
The Proust pattern has also become a design signature of Mendini's, he has used it on many of his design objects. It is reminiscent of the paintings by the 19th century 'Pointillist' artist Georges Seurat. Seurat painted with dots of colour rather than with brush strokes.
Proust Swatch by Alessandro Mendini. Mendini was the art director at Swatch.
Mendini coffee maker by Alessi. Mendini was the design director at Alessi.
Mendini corkscrews made by Alessi.
