Louis Tullius Joachim Visconti (Rome February 11, 1791 – December 29, 1853) was an Italian-born French architect and designer.
Son of the Italian archaeologist and art historian Ennio Quirino Visconti, Visconti designed many Parisian residences, public buildings and squares, including the Place Saint Sulpice and the overall design of the Fontaine Molière, and was briefly the official architect for the Louvre under Napoleon III.
After winning second prize in the architecture section of the prix de Rome (1814) and the architecture department prize at the École des Beaux-Arts (1817), he was made architecte-voyer to the 3rd and 8th arrondissements of Paris in 1826, curator of the 8th section of public monuments in Paris (made up of the Bibliothèque royale, the monument on place des Victoires, Porte Saint-Martin, Saint-Denis and the colonne Vendôme) in 1832, divisional architect in 1848, and government architect in 1849.
Visconti died of a heart attack in 1853, the year of his election to the Académie des Beaux-Arts.
He is buried in Pere Lachaise Cemetery in Paris with a full size reclining figure of himself on the tomb.