What is the name of the underground exhibition in the Louvre displaying the medieval fortress remains?

The underground Louvre exhibition displaying the medieval fortress remains is called the Medieval Louvre.

The exhibition preserves parts of the castle that stood on the site before the palace became the vast museum complex known today. King Philip II began the fortress around 1190 as part of Paris’s defensive system, and it was completed around 1202. Its walls, moat, towers, and great central keep made it a serious military structure on the city’s western approach.

Although the medieval castle was gradually demolished between the sixteenth and seventeenth centuries to make way for the expanding Louvre Palace, substantial foundations survived underground. Large-scale excavations connected with the Louvre Pyramid project uncovered the keep’s base, sections of the curtain walls, and objects from everyday medieval life.

The Medieval Louvre is therefore an archaeological display as well as an architectural one. Visitors can see stone remains and finds such as pottery, jugs, flasks, dice, and other games. It should not be confused with the Salle des Caryatides, a later palace room, or the Roman Baths at the Musée de Cluny.