The 26-year-old, who can play at right-back or centre-back, has agreed a two-year contract with the O's, with the option of a further year.
Erichot came through the youth ranks at AS Monaco and has also had spells on loan at Clermont and Unaio Leiria.
He is Orient's sixth signing of the transfer window.
Meanwhile, academy coach Danny Webb has been appointed first-team coach as the Matchroom Stadium.
Find all the latest football transfers on our dedicated page.
League Two side Leyton Orient have signed French defender Yvan Erichot following his departure from Belgian Jupiler League side Sint-Truiden.