Fashionistas, take note. As we reported back in September 2011, the shoe designer Christian Louboutin attempted to prevent Yves Saint-Laurent (YSL), the fashion house, from selling red shoes with red soles, on the grounds that Louboutin had registered a trade-mark in red-soled shoes. The District Court in Manhattan doubted that a single colour could be the subject of an enforceable trademark, and declined to issue an injunction. Louboutin appealed, with mixed success: Christian Louboutin SA v Yves Saint Laurent Holdings Inc (2d Cir, 5 September 2012).

The Second Circuit reasoned that the judge below had erred in thinking that a single colour could never be the subject of trade-mark protection, having misunderstood earlier case law and the concept of ‘aesthetic functionality’ (which sounds like a contradiction in terms, but whatever...) Louboutin’s red-soled shoes are distinctive and his trade-mark in them clearly enforceable, but this is predicated on there being a contrast between the red of the soles and the colour of the shoe’s upper. Louboutin’s rights in the red-sole mark do not prevent someone else (like YSL) from producing a shoe that is red from top to bottom, with no contrast between upper and sole.