Oyongo, 26, joined the Impact ahead of the 2015 season after spending one year with the New York Red Bulls. He made 60 league appearances for the club and established himself as one of the better left backs in MLS during his time in Montreal. The 26-year-old only played in 11 matches this year before a ruptured patella tendon suffered on international duty in June sidelined him for the rest of the year. His MLS contract will expire at the end of 2017.
Montpellier, the 2011-12 Ligue 1 champions, are in eighth place through 12 matches of the 2017-18 season.