Celebrities have unique problems,” says Tom Hayes, Paramount’s VP of studio protection. Apparently, obeying gun laws is one of them. Here’s the 411 on celebs caught packing heat:

— ROBERT DOWNEY JR.’s downward spiral began June 23 when he was charged with driving under the influence, cocaine and heroin possession, and having an unloaded .357 Magnum in his truck. ”I thought [the gun] was cool,” Downey later said. ”[But not] so cool that I wanted to have it loaded.”

— Police pulled over LARRY FORTENSKY Sept. 15 for riding his Harley-Davidson without a helmet. Upon finding that he had an expired license and an invalid registration, they impounded his bike and discovered a 9 mm semiautomatic in the saddlebag, leading to his second arrest within a month.

— Less than three months after police found him armed and screaming on an L.A. street in May (charges were never filed), MARTIN LAWRENCE tried to carry a 9 mm semiautomatic onto a July 29 Southwest Airlines flight to Phoenix. Police detained the comedian, who claimed he thought boarding with a gun was okay since he was traveling out of state. Then he said he didn’t know he had the gun; later, he pleaded no contest, got two years’ probation, and paid a $500 fine.

— The smell of marijuana prompted Teaneck, N.J., police to search the home of rapper NOTORIOUS B.I.G. July 23. In addition to 50 grams of pot, they found a Tec-9 pistol with a 30-round clip, two guns with laser sights, and a revolver — all without serial numbers, indicating they might have been stolen.

— Seven months after surviving a carjacking, rapper-actress QUEEN LATIFAH admitted to the California police who stopped her for speeding Feb. 3 that she’d been smoking marijuana and had a .38-caliber gun in her car. After pleading no contest to the weapons charge and to driving without a valid license, she received two years’ probation; paid $910 in fines, penalties, and restitution; and donated $2,500 to charity. ”I was down,” Latifah has said. ”It was that time of the month; it was a full moon.”

— Erin Richter, with additional reporting by Jennifer Pendleton