The retired striker believes the reason why the French champions have struggled this season is due to a lack of firepower, and advises them to shape up ahead of Tuesday's clash.
La Paillade go into their UEFA Champions League clash with Olympiakos on Tuesday on the back of a draw at Troyes over the weekend, as they try to reverse the outcome of their last fixture in October against the Greeks, when they fell to a 2-1 defeat.
"When [Giroud] played, their teammates felt more secure," said the one-time Ballon d'Or winner and ex-France international. "Other teams do not fear Montpellier anymore. They no longer fear that a guy will come along and change everything.
"The players change, but they [the strikers playing now for Montpellier] are not pure goalscorers. They score from time to time, but not in every game [like Giroud]."
Montpellier sits at bottom Group B, with one point to its name, and the defending Ligue 1 champion entered the day trailing group leader Schalke by six points.