France SYW: Penthièvre Cavalry

Most Royal French cavalry regiments wore dark blue coats whereas most non-Royal regiments looked like this one - with light grey coats and red facings. But in fact this is a Royal regiment as it's owner was Louis Jean Marie de Bourbon, duc de Penthièvre, probably the richest man in France and at the centre of the Royal family. See his most interesting biography here:

http://en.wikipedia.org/wiki/Louis_Jean_Marie_de_Bourbon,_Duke_of_Penthi%C3%A8vre

Quite why this regiment used this colour scheme is unknown but it was raised in 1674 as a non-Royal regiment so perhaps nobody noticed in almost 100 years.