That's according to a reporter who was also detained for six hours upon arrival at Narita Airport while on assignment.
"They treat you like a criminal," said the journalist, who spoke to E! News on the condition of anonymity. "They bring you in a van from the airport and take you in the back stairs of the hotel."
And we're not exactly talking a five-star joint...
"They call her accommodations a 'hotel' but it's actually a rest house. I was assigned a 24-hour security guard that was stationed outside my door to ensure I did not escape into the country," the journalist says.
There was definitely no room service available, either, so Paris likely had only vending machines to eat from.
"You can only eat the food in the vending machines, and the Japanese breakfast they served in the morning," the reporter says. "It was awful."
Paris was detained at the Tokyo-area airport on Tuesday, after being denied entry due to her guilty plea in a Las Vegas drug case a day earlier.
She was grilled for hours by immigration officials, who even phoned up her prosecutor, E! News has learned.
"The Japanese consulate called and asked for a copy of the plea agreement and amended complaint," says Las Vegas District Attorney David Roger.
"They asked if she could appeal her conviction. I told them the answer is in the plea agreement in which she had waived her right to appeal."
According to the Japanese Ministry of Justice, entry into the county can be denied upon arrival for several reasons, including: "A person who has been convicted of a violation of any law or regulation of Japan or of any other country relating to the control of narcotics, marijuana, opium, stimulants or psychotropic substances, and has been sentenced to a penalty."
Hilton, 29, pleaded guilty to possessing cocaine and was sentenced to probation, outpatient drug treatment and community service.
The unexpected airport sojourn led Paris to cancel her whole trip to Asia and just landed back in Los Angeles.
—Additional reporting by Soo Youn
Check out Paris' stylish court appearance in our gallery.