He studied chemistry and mechanics at Ecole Centrale in Paris.
Poitevin became a chemical engineer in 1843, and in 1848 worked as a chemist for the Mines Nationales de l'Est. For several years he worked independently, then returned to engineering in 1869 at a silver mine at Kefoun-Theboul in Africa.
The chemist became interested in photography after the announcement of Daguerre's and Talbot's discoveries and began experimenting with daguerreotype plates. His experiments led to a method of photochemical engraving with silver or gold on metal plates, and his discovery of the action of light on bichromated gelatin laid the basis for photolithography, the carbon process and collotypy. His various patents, held in France and England, included those for collotype and carbon printing (1855-56) and for a direct positive process (1860, 1863).
He received the Prix Marquis d'Argenteuil from the Société d'Encouragement des Arts as well as their silver medal, and they helped him several times financially. In 1878 Poitevin received a gold medal for his work at the International Exposition of Paris.