 He was a participant in the competition for the design of Place Louis XV.Named chief architect to the hôpital général in 1724, he constructed in the Île de la Cité a foundling hospital, the "Hôpital des Enfants Trouvés" (1727, demolished).Boffrand also worked for the hospitals at the Salpêtrière, at Bicêtre, and at the Hôtel-Dieu.