Adidas has filed a formal lawsuit in a New York federal court for copyright infringement against Thom Browne, according to The Fashion Law, charging that the New York-based menswear designer is “selling athletic-style apparel and footwear featuring two, three or four parallel stripes in a manner that is confusingly similar to Adidas’ three-stripe mark.” The filing says that Adidas failed to resolve the dispute through a mediation process that began last November.

Adidas had previously filed an opposition with the U.S. Patent and Trademark Office’s Trademark Trial and Appeal Board (TTAB) against a related trademark application filed by Browne in February.