Former Senegalese international Camara, 32, will remain in southern France until June 2017 with Deplagne staying until June 2018.
Camara arrived at the club in July 2007 on loan from Nice, winning the Ligue 1 title for the first time with the club in 2012, and scoring 56 goals in 261 matches.
Deplagne, 23, who has played 44 top flight matches, extended his deal by two years.
Montpellier are sixth in the league, 13 points behind leaders Lyon.