In other countries than France ?
Taiwan : National Freeway Sections and Hours for Opening of Road Shoulders
Wikipedia : "Shoulder - Reserved area by the verge of a road, generally it is kept clear of all traffic"
Informations from : http://www.geocities.com/jusjih/roadsigns.html
My interpretation could be faulty !
Found on Wikipedia. http://en.wikipedia.org/wiki/Warning_sign
Thanks to Marina Duhamel-Herz