Haarith bin Suraij (rahimahullah) narrates the following:

I was once with Imaam Shaafi‘ee (rahimahullah) when we entered into the presence of a servant of the ruler, Haaroon Rasheed. This servant happened to be in a home of which the floor was covered with a carpet of silk. When Imaam Shaafi‘ee (rahimahullah) placed his foot on the doorstep to enter, he noticed that the floor was covered in silk and immediately moved back, refusing to enter. The servant saw his reluctance to enter but did not understand the reason and thus prompted him saying, “Please enter.” Imaam Shaafi‘ee (rahimahullah), however, refused to enter and said, “It is not permissible to use silk as a carpet.” On hearing this, the servant immediately stood and took them to another home which had an Armenian carpet. Imaam Shaafi‘ee (rahimahullah) now entered and said to the servant, “This carpet, despite being better and more expensive than the silken carpet, is permissible for us on account of Sharee‘ah making it Halaal for us, whereas the silken carpet, though less in value, is impermissible, as Sharee‘ah has made it haraam for us.” When he heard the explanation of Imaam Shaafi‘ee (rahimahullah), the servant merely smiled and remained silent.

(Aadaab-ush-Shaafi‘ee wa Manaaqibuh pg. 76)

Note: According to Imaam Shaafi‘ee (rahimahullah), it is impermissible for a male to use a carpet of silk. There is a difference of opinion among the other Imaams regarding this mas’alah.