Loudmouth laugh queen Joan Rivers will not face criminal charges for her temper tantrum in an Upper East Side car-rental agency -- despite allegedly nailing a clerk in the eye with a tossed marker, The New York Post has learned.

Sources said cops were notified Monday by the Manhattan district attorney that Rivers will not be arrested or charged for the Dec. 20 pen-pitching incident at the Dollar Rent A Car on 157 E. 84th St., where Griselda Santana, 38, suffered an eyelid contusion.

Rivers, 69, allegedly cursed at Santana for making her wait for service, saying: "Don't you know who the [explitive] I am? How could you let me wait on line? You stupid . . . bitch!"

The only applicable charge would have been harassment, but that requires a cop witnessing the incident, sources said.

Some cops were miffed by the decision, saying Rivers should at least have been slapped with third-degree assault in the attack, which they labeled a form of "reckless endangerment."

When Santana arrived at her apartment in the High Bridge section of The Bronx, a bouquet of flowers were waiting for her, but it was unclear who sent them.

"I don't want to seem rude, but I don't have any comment right now," Santana said.

Santana has not returned to work since the incident, and she continues to get treatment on the eye struck by River's yellow marker, her co-worker Albert Baretto said. "What she [Rivers] did was wrong. She hurt her," Baretto said. "She still has a lot of problems with her eyes."

Rivers' spokesman, Richard Grant, said his client is currently making the rounds of awards shows and had no comment on the alleged attack, which he said "was not an incident."

Baretto said he also wasn't surprised that Rivers won't be arrested or charged.

"What she did is nothing new. She has a reputation," Baretto said.

A spokeswoman for the Manhattan DA's Office denied that the case was closed, saying, "We've made no decision."