"Rolland Courbis is to join the club on Monday," Montpellier said on their website (www.mhscfoot.com).
Fernandez quit on Thursday after a 2-0 home defeat by Lorient a day earlier left the club fourth from bottom in Ligue 1.
Former Montpellier player and assistant coach Pascal Baills had been named coach on a caretaker basis.
Courbis, a Montpellier coach from 2007-09, also had spells at Olympique Marseille, Girondins Bordeaux, RC Lens and AC Ajaccio.
The 60-year-old was sentenced to two years in prison in 2007 for his role in financial irregularities relating to transfer deals at Olympique Marseille. He spent seven months behind bars.