Citroen Xsara Picasso need to take inside door panel off

Sounds like the window has come out of the slide at the bottom of the window, you should be able to pull the switch out without removing the door card. Then take a look for any screws behind the interior door catch and handles. Once you have removed the screws, then the door card will be held onto the door by push clips. Be careful not to damage these when pulling the door card off the door.