Battle of the saints: YSL accused of stealing Louboutin's sole

In a Lenten lawsuit filed yesterday, Christian Louboutin has accused the house of Yves Saint Laurent of tarnishing the late designer's halo by copying Louboutin's trademarked red soles. 

But is this a cardinal (red) sin, legally speaking, or another fling with the aesthetic functionality defense that Counterfeit Chic has previously surmised may be a loophole protecting other apparent red-on-red ripoffs?
YSL red sole cropped.jpg
YSL sandal on
In several of its styles, YSL created not only red shoes with red outsoles, but also purple with purple soles and black with black soles.  Will the company claim that the offending red sole was a non-trademark use chosen simply to match the upper portion of the shoe, thus transubstantiating the otherwise trademarked red sole into a defensible design detail?  With two such successful and storied luxury brands battling it out, we may finally learn whether or not this legal doctrine will be hurled from high heel heaven.

Little-used law aside, however, Counterfeit Chic is somewhat surprised that designers for the distinguished house of YSL would walk where angels fear to tread and hopes that Christian isn't thrown to the legal lions.

UPDATE:  Complaint here.

ADDITIONAL UPDATE:  Answer and counterclaim here.