This floor is antique reclaimed terra cotta tile (also called parefeuilles). It can be found at dealers who specialize in European import of building materials. It was originally used as a ceiling material, spanning between ceiling or roof rafters.

A similar look can be achieved using reclaimed Chicago Brick, or using the right color and type of saltillo tiles installed upside down with a grout wash.

dzozaz,
Thank you very much. I was looking at those reclaimed imported tiles but the price was out of my budget, grout washing the back sides of the saltillo is genuis!