Montpellier joined Toulon in the Heineken Cup quarter-finals after beating the Pool Six winners to finish second in the group and secure one of the two best runners-up spots.
A Jonny Wilkinson penalty gave Toulon an early lead but Thomas Combezou's converted try put the hosts in front.
Three Benoit Paillaugue penalties made it 16-3 to Montpellier at half-time.
And Paillaugue converted his own try as Montpellier stretched clear of their Mediterranean neighbours.
Montpellier: Berard; Nagusa, Combezou, Fernandez, Audrin; Trinh-Duc, Paillaugue; Nariashvili, Creevy, Bustos, De Marco, Gorgodze, Bias, Beattie, Tulou.
Replacements: Gonzalez Amorosino for Nagusa (75), Escande for Paillaugue (73), Watremez for Nariashvili (56), van Vuuren for Creevy (62), Fa'amausili for Bustos (73), Fakate for De Marco (62), Galletier for Gorgodze (66), Privat for Tulou (41).
Toulon: D Armitage; Wulf, Mermoz, Giteau, Palisson; Wilkinson, Michalak; Sheridan, Ivaldi, Kubriashvili, Shaw, Suta, Gunther, S Armitage, Masoe.
Replacements: Bastareaud for Mermoz (66), Hayman for Kubriashvili (41), van Niekerk for Gunther (61), Fernandez Lobbe for S Armitage (50).
Not Used: Orioli, Jenkins, Kennedy, Martin.
Sin Bin: D Armitage (34).
Ref: Alain Rolland (Ireland).