On Thursday, the federal court of justice in Karlsruhe, Germany, ruled that Birkenstocks were not “copyrighted works of applied art,” making it harder for the 251-year-old German shoemaker to combat the widespread sale of duplicates of its sandals across the internet.

The shoe manufacturer claimed its sandals “are copyright-protected works of applied art" that may not simply be imitated. Under German law, works of art enjoy stronger and longer-last intellectual property protections than ordinary consumer products.

In a lawsuit, Birkenstock aimed to combat knockoffs, but the court determined the German footwear does not meet the definition of “applied art.”