The socialite, 26, surrendered herself to the prison just before midnight on Sunday (local time) after attending the glitzy MTV movie awards.
She has been in a tiny cell in solitary confinement since then for her own protection.
Paparazzi photographers and TV crews were swarming round the jail from around 11pm local time on Wednesday (7am Thursday UK time) hoping to catch the socialite leaving.
It is thought a deal was made last night.
Paris has been crying herself to sleep during her stint behind bars.
