It looks like art silk aka viscose. A lot of high street stores have designer pop ups within them. Typically Mulberry, D & C, Chanel, Jimmy Choo and many others have this high end viscose product on the floor. It is often in the form of a rug. As you are finding out it is a nightmare to keep clean. Dry compound is recommended but with caution you can often do low moisture encap with contra rotating brush machines, not rotary. I have also wet extracted them but keep the moisture low and don't scrub just spray and dry. Lots of dry vacuuming first. PP