Sanson entered the École des Beaux-Arts de Paris at the age of eighteen, and followed the courses offered by Émile Gilbert.
Having received his diploma in 1861, he was apprenticed first in the office of Denis-Louis Destors and Charles-Auguste Questel and then with Antoine-Nicolas Bailly, who passed his practice to Sanson when he retired in 1865.
Sanson distinguished himself with his tasteful residences in the grand manner, which combined the great architectural tradition of French design of Mansart and Gabriel, with modern amenities of plumbing, heating, and the discreet separation of owners and guests from the supporting staff.
In 1861, Sanson married Marie-Caroline Scelles, with whom he had two sons, Maurice Pierre (1864–1913) and Louis Charles (1866–1917).
Outside France Sanson worked in Belgium, New York, Madrid, Washington, Buenos Aires and Córdoba, Argentina.