Église Saint-Eustache (English) was built between 1532 and 1632. Next to Paris ’s Les Halles (pronounce), this church is a masterpiece of late Gothic architecture. It served as the location for the first communion of Louis XIV and Mozart's mother’s funeral. Among those baptised here as children were Richelieu, Jeanne-Antoinette Poisson, the future Madame de Pompadour, and the playwrite Molière, who was also married here during the 17th century.

With its 8000 pipes, the organ is reputed to be the largest in France, surpassing the organs of Saint Sulpice and Notre Dame de Paris. The organ was originally constructed by Ducroquet and later modified under the direction of Joseph Bonnet. The present instrument was designed under the direction of Titular Organist Jean Guillou and dates from 1989 and was built by the Dutch firm of Van den Heuvel retaining a few ranks of pipes from the former organ.