Case Closed

Mister Louboutin Did not want anyone to make anything with red soles at all!
Last year Zara won the right to make red soled heels as well
Victory: Last year Zara won the right to sell their red-soled heels (left) which Louboutin said copied their Yo Yo slingbacks
 However in this case Louboutin won the right to the red sole and YSL won the right to continue producing the monochromatic red  shoes. Its a win win.

The law recognises that, in the right context, a single colour can become distinctive of particular goods or services - such as purple for Cadbury's chocolate, or green for BP service stations. But it is all about context - in the right situation, red might be associated exclusively with London buses, but nobody would think a red pillar box was connected with London buses. So the New York court held that, in the right situation, a lacquered red sole on footwear was associated exclusively with Christian Louboutin and they were entitled to trade mark protection - but it also held that it was the flash of the red sole (on a shoe of a contrasting colour) that was an important factor in making this association. So the New York court held that Christian Louboutin could not prevent YSL from selling their monochrome red shoe (which, even though it had a red sole, did not give the impression of a shoe with a red flash).So, as an overall comment, a single colour such as that used for the sole of a Christian Louboutin can distinguish the goods from those of competitors - but whether it will depends on the context in which 
Ian Wood, Partner in Intellectual Property at it is used.  In this case, as part of a monochrome red shoe, it was not distinctive.'Charles Russell LLP