We stayed at the Palais Royal couple of times. The location is brilliant, right next to the Jardin du Palais Royal and 250 m north of the Louvre. The hotel overlooks a lovely little square call the Place de Valois. When we stayed, one of the two accessible rooms look north onto this little square through generous windows opening onto a little terrace. Lots of sun and fully accessible, right in the middle of Paris; unbelievable.
Since then, the hotel is had a major makeover. Already expensive, prices have now doubled. Although I’m sure they still have accessible rooms, I shouldn’t be surprised if they moved the wheelchair accessible room elsewhere as the view over the square was delightful. If your budget can stand it, stay there and let me know how you went.
The going rate in high season is about $800 Australian per night, but you’ll be pushed to get a room unless you book a year in advance.