The Church of St. Eustache, Paris, is a church in the 1st arrondissement of Paris. The present building was built between 1532 and 1633. Situated near the site of Paris' medieval marketplace and rue Montorgueil, Saint-Eustache exemplifies a mixture of multiple architectural styles: its structure is Flamboyant Gothic while its interior decoration and other details ar…The Church of St. Eustache, Paris, is a church in the 1st arrondissement of Paris. The present building was built between 1532 and 1633. Situated near the site of Paris' medieval marketplace and rue Montorgueil, Saint-Eustache exemplifies a mixture of multiple architectural styles: its structure is Flamboyant Gothic while its interior decoration and other details are Renaissance and classical. It is the second largest church in the city, just behind Notre-Dame.