At the age of 27, he left for Paris to study Indology with Eugène Burnouf.

After becoming aware of the work of Sándor Kőrösi Csoma, he studied Tibetan by himself for two years.

After this he was appointed as a Tibetan teacher at the École des langues orientales where he gave his inaugural lecture on 31 January 1842.

[1] Funding for the position was canceled but Foucaux continued to instruct his students thereafter on a pro bono basis.

Some of his most well-known students include Léon Feer [fr], William Woodville Rockhill, and Alexandra David-Néel.