The entrance of the Conciergerie, called the Hall of Guards, is breathtakingly beautiful. Walk through a major focal point of the French Revolution and see the jail cells where prisoners were kept (including Marie Antoinette). There was a modern art exhibit in the main hall when we visited.
When you enter Sainte-Chapelle you will see a few exhibits and shops; but the second floor is the actual chapel. Enter the second floor and you will see the stained glass that is so beautiful and bright even on a rainy day.
Entering the first level of Sainte-Chapelle, you will notice that the glass and ceiling are beautiful with many areas to explore and things to do. Conciergerie is a great parisian heritage filled with cultural artifacts. They both are a masterpiece in Paris.