The Palais de Justice (French pronunciation: [palɛ d(ə) ʒystis], lit. 'Palace of Justice') is a judicial centre and courthouse in Paris, located on the Île de la Cité. It contains the Court of Appeal of Paris, the busiest appellate court in France, and France's highest court for ordinary cases, the Court of Cassation. It formerly housed the Tribunal de grande instance de Paris which was relocated in 2018 to a new high-rise building in Paris's Batignolles neighbourhood.

The Palais de Justice occupies a large part of the medieval Palais de la Cité, the former royal palace of the kings of France, which also includes Sainte Chapelle, the royal chapel, and the Conciergerie, a notorious former prison, which operated from 1380 to 1914. It is located in close proximity to the Tribunal of Commerce, the Prefecture of Police of Paris, and the offices of the Paris Bar Association.

Under King Robert II of France the Palais de la Cité began to serve as the home of a high court or council for the King. He constructed the Hall of the King, where the Curia Regis, or King's Council met. This was replaced by a much larger hall, the Grand Chamber, under Philip IV (1268–34). This enormous hall began to be used for theatrical performances, the meetings of the Parlement of Paris, a judicial body composed of the high French nobility.

In 1358, a Paris uprising led by the merchant Etienne Marcel caused the future king, Charles V of France, to depart Paris for safer quarters farther from the center of Paris; first at the Hôtel Saint-Pol, then near the Bastille, then the Louvre Castle. The judicial function, however, remained at the old palace. The Parlement of Paris, meeting in the Grand Chamber, was an appeals court for royal tribunals and the court of first instance in cases involving the nobility. Furthermore, its approval was required for royal ordinances. This gave it growing power in the feuds between the monarchy and the nobility. Louis XV attended his first court session there in 1715 at age five. The other judicial offices that remained were the Chambre des comptes and the Chancellery.

The very decorative gilded wrought iron grillwork and gateway were put in place in 1776. The façade and principal entrance of the palace, facing the Court of May, was entirely rebuilt between 1783 and 1786 with a neo-classical colonnade.^{[citation needed]}

During the French Revolution, the Grand Chamber, where the Parlement of Paris had met, became the courtroom of the Revolutionary Tribunal, which rapidly tried and sentenced those accused of opposing the Revolution. Those convicted were usually taken to the guillotine the same day. In 718 days, up until 31 May 1795, the Tribunal sent 2,780 persons to the guillotine. Among the last to be executed was the Chief Prosecutor, Antoine Quentin Fouquier-Tinville, bringing the Reign of Terror to a close.

In the first half of the 19th century, the palace became entirely devoted to the justice system. Under the reign of Napoleon Bonaparte, the Restoration and the July Monarchy, various projects were put forward for a new and larger structure. Between 1820 and 1828, the architect Antoine-Marie Peyre built a new façade between tower of the Horloge and the Tower of Bombec, and the access to the Conciergerie was moved to the Quai de Bombec.^{[citation needed]}

Between 1837 and 1840, a new project for the building was developed by the architect Jean-Nicolas Huyot. Unlike most of the proposed structures, which were in the neo-classical style, with columns and pediments, Huyot's plan was neo-Renaissance. Unfortunately, on August 3, 1840, after all the final approvals had been received, Huyot died. Two weeks later the architects Joseph-Louis Duc and Etienne-Theodore Dommey were selected to build the structure. Construction took place between 1847 and 1871. The project included a new façade on the Boulevard de Paris, the restoration of the other buildings within the old palace, and a new building for the Cour de Cassation.^{[citation needed]}