You don't have sole right to red soles, YSL tells Louboutin

When Christian Louboutin sued Yves Saint Laurent for trademark infringement last month in a legal tussle over a pair of shoes, it was clear the accused, one of the grandest labels in France, would not take the slur lying down.

Now YSL is fighting back in a dispute which started with a collection of pumps. The best-selling styles, including the Tribute, the Palais and the Woodstock, came with coloured soles which perfectly matched their leather uppers. It was the red shoes Louboutin and his legal advisors took exception to.

Louboutin's designs have been spotted on the feet of celebrities from Oprah Winfrey and Carla Bruni to Victoria Beckham and Beyoncé Knowles. The designer is among the most prolific on the international catwalks and, in his case, the prized instant recognition which is fashion's life blood comes with his poppy-red lacquered soles.

Louboutin claims to have introduced his trademark in the early Nineties while studying a prototype. "There was this big, black sole," he told The New Yorker recently, "and then, thank God, there was this girl painting her nails." He swiftly used the enamel in question to cover the shoe and one of fashion's status symbols was born.

Or so he thought. YSL argues that Louboutin has no monopoly on the colour – on the soles of his shoes or indeed elsewhere – and that its shoes have sported red soles since the Seventies. "Red outsoles are a commonly used ornamental design feature in footwear, dating as far back as the red shoes worn by King Louis XIV in the 1600s and the ruby-red shoes that carried Dorothy home in The Wizard of Oz," said court papers filed by Yves Saint Laurent and released this week.

"As an industry leader who has devoted his entire professional life to women's footwear, Mr Louboutin either knew or should have known about some or all of the dozens of footwear models that rendered his sworn statement false."

Louboutin, 47, is seeking damages of $1m (£620,000) from YSL which, he argues, has copied his signature sole on "virtually identical" shoes. According to court documents, Louboutin, which sells more than 500,000 pairs of shoes in more than 40 countries, was awarded a registered trademark for its red sole by the US Patent and Trademark Office in 2008.

"The shiny red colour has no function other than to identify to the public that they are mine," the designer told a court in his application. With this in mind, Louboutin has, in the past, obtained injunctions against several companies attempting to replicate it, including, last February, Kimera International, which was found to have "engaged in acts of trademark counterfeiting and trademark dilution." Taking on a name with the clout of Yves Saint Laurent, today owned by PPR (Pinault-Printemps-Redoute), among the largest luxury goods conglomerates in the world, is another matter.

Charles Colman, a New York-based intellectual property rights lawyer told trade paper Women's Wear Daily that any litigation was likely to prove a long, drawn-out affair. "When you're dealing with two large parties, both of which have large and skilled law firms working for them, you don't have that leverage differential that you may have in other situations," he said, going on to point out that it was also less likely that inflated legal fees would run either party into the ground.