Alexa

In 2006 I went to the Guggenheim Museum in New York and saw this painting of a man that still haunts my mind's eye. I'm not an art expert but I will describe the painting as best as I can...

He had a rather expressive face, with blue eyes, curly blonde hair up to his shoulders and a light blond mustache over his lips. I think he had a french musket tucked into his belt and a rosary with a gold medallion and a gold crucified jesus hanging from it. He had a dark cape around his shoulders with purple velvet lining it's interior. He wore a blue french militia jacket and a yellow, red and blue scarf. A hat with a white feather hung behind him. I think he was an aristochrat of the French Royal family but I'm not sure.

Could anyone tell me who he is or who was the painter?? I will be very grateful for any info!

Thanks!!