LOS ANGELES - A judge yesterday sentenced Paris Hilton to 45 days in county jail for violating her probation, putting the brakes on the hotel heiress' famous high life.

Hilton, who parlayed her name and relentless partying into worldwide notoriety, must go to jail on June 5 and she will not be allowed any work release, furloughs, use of an alternative jail or electronic monitoring in lieu of jail, Superior Court Judge Michael T. Sauer ruled after a hearing.

The judge ruled that she was in violation of the terms of her probation in an alcohol-related reckless- driving case.

"I'm very sorry and from now on I'm going to pay complete attention to everything," she told the judge before he announced the sentence. "I'm sorry and I did not do it on purpose at all."

She was then ordered to report to a women's jail in suburban Lynwood on the set date or face 90 days behind bars. The judge's ruling excluded her from paying to serve time in a jail of her choice, as some are allowed to do.

When a city prosecutor said during closing arguments that Hilton deserved jail time, Hilton's mother, Kathy, laughed. When the judge ruled, Kathy Hilton, then blurted out: "May I have your autograph?"

Paris Hilton was among a series of witnesses who took the stand during the hearing. She testified that she believed her license initially had been suspended for 30 days and that she was allowed to drive for work purposes during the next 90 days.

She said that when an officer who stopped her in January made her sign a document stating her license was suspended, she thought he was mistaken and did not check the document.

Also called to the stand was Hilton's spokesman, Elliot Mintz. Hilton and her attorneys characterized Mintz as a liaison between Hilton and her lawyers.

Mintz testified that to his knowledge Hilton did not drive during the 30-day period. He said he then advised her that he believed her license was no longer suspended.

The judge called Mintz's testimony worthless and expressed disbelief at Hilton's lawyers.

"I can't believe that either attorney did not tell her that the suspension had been upheld," the judge said. "She wanted to disregard everything that was said and continue to drive no matter what."

Hilton looked forward and didn't speak to news media as she left court. Her mother looked upset.

When a reporter asked what she thought of the judge's decision, a visibly angry Kathy Hilton responded: "What do you think? This is pathetic and disgusting, a waste of taxpayer money with all this nonsense. This is a joke."

Defense attorney Howard Weitzman said he would appeal.

"I'm shocked, I'm surprised and really disheartened in the system that I've worked in for close to 40 years," Weitzman said.

He said the sentence was "uncalled for, inappropriate and bordered on the ludicrous."

"I think she's singled out because of who she is," Weitzman said.

Hilton had arrived at the Metropolitan Courthouse 10 minutes late and ignored screams of photographers as she swept in with her attorneys, mother and father, Rick Hilton. Wearing a gray jacket and white shirt over black slacks and with a black headband on, she said nothing and appeared serious.

Hilton, 26, pleaded no contest in January to reckless driving stemming from a Sept. 7 arrest in Hollywood. Police said she appeared intoxicated and failed a field sobriety test. She had a blood-alcohol level of 0.08 percent, the level at which an adult driver is in violation of the law.

She was sentenced to 36 months' probation, alcohol education and $1,500 in fines.

Two other traffic stops, and failure to enroll in a mandated alcohol education program, are what landed the socialite back in court.

Hilton, heiress to the Hilton Hotel fortune, first gained notoriety for her hard partying as a teen. She attracted worldwide attention when a sex tape she made with a boyfriend was released on the Internet.

She stars in the reality-TV series, "The Simple Life," now in its fifth season, with Nicole Richie. She appeared in the 2005 film "House of Wax," and recently finished filming "The Hottie and the Nottie." *