French shoemaker Christian Louboutin can trademark his famous red soles, a United States court has ruled, reversing a previous ruling that had allowed rival Yves Saint Laurent (YSL) to paint its soles scarlet as well.
The case featured two of the fashion world's heaviest hitters in a battle to own the glossy red outsole that Louboutin says is at the heart of its shoes' appeal.
The sexy heels are a favourite among celebrities like Lady Gaga and Victoria Beckham.
Last year, a New York federal judge ruled that Louboutin's red accent may be widely recognised, but that it was not enough to prevent competitors from doing the same thing.
But on Wednesday, a US court of appeal overturned the ruling, saying that red soles, in contrast with the colour on the upper part of the shoe, are "entitled to trademark protection".
Louboutin said it was "extremely pleased and gratified that the Appellate Court found our key arguments to be correct".
Meanwhile, the decision was a setback for fellow French luxury brand YSL, which had celebrated in August last year when US District Judge Victor Marrero ruled that Louboutin could not claim a colour as its own.
Marrero had said at that time: "Because in the fashion industry, colour serves ornamental and aesthetic functions vital to robust competition, the court finds that Louboutin is unlikely to be able to prove that its red outsole brand is entitled to trademark protection.
But the latest ruling on Wednesday did leave some wiggle room. Scarlet soles are still allowed for other brands - as long as the whole shoe is red.
The YSL shoe that drove Louboutin to court was red from top to bottom, which is in fact allowed, the appeals court said.
"Because Louboutin sought to enjoin YSL from using a red sole as part of a monochrome red shoe, we affirm in part the order of the District Court insofar as it declined to enjoin the use of red lacquered outsoles in all situations," the ruling said, making the distinction with "contrasting red" shoes.
Louboutin, which has marketed shoes with red outsoles since 1992, registered the look as a trademark in the US in 2008.
About 240,000 pairs of the hot heels, which featured in the fashion-focused television series Sex And The City, are sold each year in the US alone, making revenues of about US$135 million.
A pair typically costs between US$700 and US$1,000, but can sell for far more, with the Lady Peep Geek Embroidered Pump listed at US$1,695 in the Neiman Marcus department store.
Marrero wrote in his ruling last year: "When Hollywood starlets cross red carpets and high-fashion models strut runways and heads turn and eyes drop to the celebrities' feet, lacquered red outsoles on high-heeled, black shoes flaunt a glamorous statement that pops out at once."
But in Wednesday's ruling, the court said Marrero's decision that a single colour could not be trademarked in the fashion industry "was based on an incorrect understanding of the doctrine of aesthetic functionality".
The court noted that leading designers, including YSL, "however begrudgingly," accepted that "the flash of a red sole" was the Louboutin signature.