Who designed the pyramid at the Louvre museum?

The pyramid was commissioned by French President Francois Mitterrand. It was designed by the architect I.M. Pei from New York, who also designed the Miho museum in Japan as well as others. It is 20.6 meters high (70 ft.) and the base is 35 meters (115 ft.) square. It has 603 Rhombus shaped and 70 Triangular Glass Segments.

The pyramid structure was engineered by Nicolet Chartrand Knoll Ltd. of Montreal (Pyramid structure / Design Consultant) and Rice Francis Ritchie, also known as RFR of Paris (Pyramid Structure / Construction Phase). Attribution is by Pei Cobb Freed and Partners.

It is an urban myth that the specification required 666 panels of glass (as quoted in the book "The Da Vinci Code" by Dan Brown). See also the related link, from which some of this information is taken.