The Ligue 1 champions were held to a 1-1 draw with Lyon at Parc des Princes on Sunday evening.
The result was their third consecutive draw, and Leboeuf, who played for Chelsea from 1996 to 2001, wants to see his compatriot make some tough calls that could save his job.
He told RMC: "I think he needs to cut the routine and put an established fact to some players: if they have a bad game, they will not be spared from being replaced because of their name.
"Can it get complicated for Laurent Blanc? Yes, it can quickly become complicated. Currently his changes are very predictable; you always know who will come out and who will return."
PSG are currently fifth in Ligue 1.