His father, Édouard Lartet was a prominent geologist and prehistorian who played a key role in the 1860s and 1870s in finding evidence that humans had lived during the Quaternary period and Louis continued his father's researches into human prehistory.
This resulted in his publication of Exploration géologique de la mer Morte (1876-7), which formed his doctoral thesis.
In 1868, Lartet was asked to conduct excavations in a rock shelter near the French village of Les Eyzies after workmen stumbled upon extinct animal bones, flint tools, and human skulls.
Lartet discovered the partial skeletons of four prehistoric adults and one infant along with perforated shells used as ornaments, an object made from ivory, and worked reindeer antler.
Sur la dentition des proboscidiens fossiles (Dinotherium, Mastodontes et Éléphants) et sur la distribution géographique et stratigraphique de leurs débris en Europe.