Hotel de Carnavalet was originally built in 1548-60 on commission by the president of the Parlement of Paris, Jacques de Ligneris. The name Carnavalet comes from its second owner, whose real name was actually Kernevenoy, or Kernevenoch.
The street front on Rue de Sevigné retains only a fragment of the original due to a rebuilding by Francois Mansart in 1655-61. However, Mansart kept the rusticated entrance arch from about 1550, which is commonly attributed to Pierre Lescot. Rusticated arches, inspired by Italian models, already existed at Fontainebleau, at Grotte des Pins or Hotel de Ferrare, but is here much smoother in texture. The relief decorations were added after the house passed to Kernevenoy and features a figure on the keystone, representing abundance, standing on top of a carnival mask, presumably as a pun on the name Carnavalet.
The single storey entrance arch was originally flanked by two pavilions of equal appearance; with ground floor, mezzanine and a top storey with pitched roofs and dormer windows. By 1654, the house had passed to Claude Boisleve, who wanted to increase the floor space. Mansart therefore built over entrance arch and created a new facade, which nevertheless does its best not to overpower the original arch. The additional relief decorations are by Gerard van Obstal.
Mansart also did his best to keep the main features of the courtyard facades, though the gallery on the left was originally a single storey and the wing on the right had been built as stables and was replaced entirely. The main block was reworked by Victor Parmentier during a restoration in 1866-70. The mullioned windows, though not the original dimensions of the windows, were returned, while the balustrades and dormers were based on an engraving from 1650 by Marot, but which probably never existed before. Decorative medallions on the ground floor were also removed and the 17th century mansard roof was replaced with a new sloping roof with a very steep pitch. The relief decorations were part of the original scheme and are allegorical representation of the seasons. They are sculpted in the style of Jean Goujon and may have been executed by him personally. The decorations on the lateral wings, as altered by Mansart, are by van Obstal and executed in the same vein as the originals on the main block.
The statue of Louis XIV was placed in the courtyard in 1890.
The original features of the garden front (right) is not known but may have included some kind of rustication. The arcade running across the middle of the garden was built by architects Felix Roguet and Joseph-Antoine Bouvard after 1871. It includes a central pavilion which originally belonged to Hotel Desmarets, a building by an unknown architect from 1710. Elements of several buildings slated for demolition were added to the new garden wings at this time, as Hotel Carnavalet had been bought by the city of Paris in 1866 and turned into a museum. This includes a frontispiece of the merchant draper's guild from 1660 by Jacques Brand and Arc de Nazareth, which belonged to Palais de la Cité and was built in 1552-56 by Guillaume le Breton.