Hi Gregoire,
I have always liked this effect of motionless verses movement in the same image. It is a shame we cannot see your exif to show what shutter speed you were using. Have you tried this same effect in a crowded area, where all of the people milling around your model show movement and your model remains perfectly still? Also a great effect.
I believe this one has been layered with a sepia tone, this in my view adds more impact than the bw version, which I prefere. Great shot
