A growing number of Senates or second chambers around the world to receive constitutional mandate to represent the local authorities of their countries. As of 1875, the French Senate has been and remains the representative of the local authorities and section 24 of the French Constitution of 4th October 1958 reaffirms this. This book aims to present a descriptive way, the specificity of the French Senate in this area, and how are relations of the Senate and Senators with local authorities and local representatives.