Can Christian Louboutin Trademark Red Soles? An E.U. Court Says No

LONDON — Can you trademark a color?

The French shoe designer Christian Louboutin — known for sky-high stiletto shoes with scarlet soles that can sell for upward of $1,000 — has been trying to do so for years. Mr. Louboutin first grabbed his assistant’s red nail polish and applied it to the outsoles of a shoe a quarter-century ago. Since then, he has frequently declared the design element to be his recognizable signature, and argued it merits legal protection.

On Tuesday, the European Union’s highest court dealt a blow to that effort.