June 7 (Bloomberg) -- Hotel heiress Paris Hilton, wearing an electronic ankle bracelet, traded a cramped jail cell for her Hollywood Hills home today after serving just three full days of a three-week sentence.

Hilton was freed for medical reasons, Los Angeles sheriff's spokesman Steve Whitmore said in a televised news conference. Whitmore wouldn't elaborate and said Hilton will spend 40 days in home confinement. She was released after her psychiatrist consulted with the jail's medical staff, CNN reported.

The decision was opposed by Los Angeles prosecutor Rocky Delgadillo, who filed a motion today with Superior Court Judge Michael Sauer to have Hilton returned to prison. Delgadillo said the sheriff's department violated the court order that Hilton be imprisoned. A hearing is scheduled for tomorrow morning on the motion, the Los Angeles attorney's office said in an e-mail statement.

In a statement released by Hilton's attorney, Richard Hutton, she thanked the sheriff's department and the staff of the Century Regional Detention Facility for ``treating me fairly and professionally.''

She added she had ``learned a great deal from this ordeal'' and hoped others had learned from her ``mistakes.''

Hilton, 26, has lived at a Spanish-style villa in the Hollywood Hills since 2005, when she paid about $3 million for the property, according to media reports.

She reported to the Lynwood, California, jail just before midnight on June 3. The Hilton Hotel heiress was housed in an 8- by-12-foot (2.4-by-3.7-meter) cell, spending 23 hours a day in solitary confinement.

Bored, Cold

The ``Simple Life'' star said she was bored, cold and sleeping poorly in a cell set apart from others for her own safety, according to the New York Daily News.

Hilton was originally sentenced to 45 days in jail on an alcohol-related reckless driving charge in January. The period was later cut to 23 days.

The full 45-day sentence was reinstated upon her release, Whitmore said. Hilton was credited with two full days for the few hours she spent behind bars on June 3 and early this morning, for a total of five days legally served, he said.

Hilton pleaded no contest to the January charge and sentenced to three years' probation. In the following month, she was pulled over twice by police, who told her she was driving with a suspended license.

To contact the reporter on this story: Demian McLean in Washington at dmclean8@bloomberg.net

Last Updated: June 7, 2007 21:17 EDT