From the Super Mario Wiki
Located in Poshley Heights, the Poshley Sanctum is Pennington's home in Paper Mario: The Thousand-Year Door. It is where the Garnet Star is located. The two main halls can be navigated by Spin jumping off the star tiles on the floor to grab the various poles near the ceiling. Some of the ledges have Paper Plane panels which Mario can use to reach the ledges on the other side of the room.
At the entrance, when Mario first walks in, the Shadow Sirens and Doopliss can be seen with the fake Garnet Star. They break a window to get away, thinking they have the real Crystal Star. To keep the actual star safe, it was hidden inside the back wall's painting. A hidden pipe behind a curtain transports Mario inside it. The painting shows a pipe outside the front entrance of the Sanctum. When Mario goes through the pipe into the painting and walks inside the Sanctum, he'll be in the room with the real Garnet Star. This new area inside the painting is almost exactly the same as the area outside the painting, except that it has different lighting and is filled with Dark Boos. There is a pipe into the painting of this room.
The first room contains a ! Switch to make the pipe appear, leading into the painting. The back room contains the L Emblem badge. Both need to be reached by using the poles near the roof to shimmy onto the wall ledges.
The in-game map description reads, "Only recently converted to a domicile, this former temple is now home to Pennington, the detective."
Names in other languages