Ozier Muhammad/The New York Times

The signature red soles on Christian Louboutin high heels, so famous they inspired a song by Jennifer Lopez and made countless cameos on “Sex and the City,” could one day show up on shoes sold at Payless.

A judge declined on Wednesday to grant a preliminary injunction requested by Christian Louboutin against Yves Saint Laurent, which was accused of trademark infringement for shoes that featured red soles similar to those of Louboutin’s. The decision not only cleared the way for Saint Laurent to continue producing its shoes, but also seemed to give coverage to other shoe manufacturers that may want to add a scarlet underpinning to theirs.

Judge Victor Marrero of Federal District Court in Manhattan ruled that the trademark Louboutin obtained in 2008 for its “lacquered red soles” — on shoes that can sell for more than $1,000 a pair — was “overly broad” and most likely not protectable.

“Because in the fashion industry color serves ornamental and aesthetic functions vital to robust competition,” Judge Marrero ruled, “the court finds that Louboutin is unlikely to be able to prove that its red outsole brand is entitled to trademark protection, even if it has gained enough protection in the market to have secondary meaning.”

The lawsuit was filed over four shoes in the Yves Saint Laurent Cruise 2011 collection: the Tribute, Taboo, Palais and Woodstock models.

Ysl.com

The court seemed to want to give Mr. Louboutin his due, however, describing in great detail the impact the French designer, who has been profiled in Vanity Fair and The New Yorker, has had on fashion.

“When Hollywood starlets cross red carpets and high-fashion models strut down 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 all at once,” the ruling stated. “For those in the know, cognitive bulbs instantly flash to associate: ‘Louboutin.’ ”

But recognition aside, the court ruled that allowing Louboutin to claim that scarlet sole as its own would have been like forbidding Monet from using a specific shade of blue in his Water Lilies series because Picasso had been there first with paintings from his Blue Period.

Louboutin’s lawyer, Harley Lewin, told Agence France-Presse: “We are profoundly disappointed at the judge’s decision. We are currently evaluating all alternatives.”