Jean-François-Thérèse Chalgrin (1739 – 21 January 1811) was a French architect, best known for his design for the Arc de Triomphe, Paris.
His neoclassic orientation was established from his early studies with the prophet of neoclassicism Giovanni Niccolò Servandoni and with the radical classicist Étienne-Louis Boullée in Paris and through his Prix de Rome sojourn (November 1759 – May 1763) as a pensionnaire of the French Academy in Rome. His time in Rome coincided with a fervent new interest in Classicism among the young French pensionnaires, under the influences of Piranesi and the publications of Winckelmann.
Returning to Paris, he was quickly given an appointment as an inspector of public works for the city of Paris, under the architect Pierre-Louis Moreau-Desproux, whose own time at the French Academy in Rome had predisposed him to the new style. In this official capacity he oversaw the construction of Ange-Jacques Gabriel's Hôtel Saint-Florentin in the rue Saint-Florentin, where Chalgrin was able to design the neoclassical gateway to the cour d'honneur.
In 1764 (Eriksen 1974) he presented his uncompromisingly neoclassical plans for the Church of St. Philippe-du-Roule (illustration; constructed 1774–1784); its colossal Ionic order of columns, which separated the barrel-vaulted nave from the lower, barrel-vaulted aisles, was carried around the apse without a break. In this church, which was built 1772-84, he revived a basilica plan that had not been characteristic of French ecclesiastical architecture since the sixteenth century.
In 1775 he was appointed First Architect to the comte de Provence, brother of Louis XVI; he designed the pavilion of the comtesse de Provence at Versailles. In 1779 he was appointed overseer of the building projects of another brother of the king, the comte d'Artois.