Court of Miracles is a place in the film The Hunchback of Notre Dame. It is located under the city of Paris in the old catacombs (the secret entrance being found in a graveyard), where the gypsies hide out from the authorities.
The Court of Miracles was really a French term which referred to slum districts of Paris, where the unemployed migrants from rural areas resided.
The graveyard where the Court is located does exist in the 20th arrondissement (administrative district) of Paris, known as wikipedia:Cimetière du Père-Lachaise. Coincidentally, the protagonist of Victor Hugo's Les Misérables, Jean Valjean, was given an honorary grave at Père-Lachaise.