He designed grandiose Neoclassical projects such as the Foro Bonaparte in Milan, which was never executed, and plans for the Procuratie buildings on St Mark's Square in Venice, which were modified and completed by others.
[2] In 1801, after the French had returned to Milan, Antolini was commissioned to draw up plans for redesigning the city in the around the Sforza Castle which Napoleon had begun to demolish.
Surrounded by a Doric colonnade, the plaza was to be bordered by administrative buildings, ministries, court houses, baths, theatres, universities and museums.
[4] Antolini's original plans were however considered to be one of the most important endeavors of Neoclassical architecture, so much so that the Foro Bonaparte was soon to inspire Naples' semicircular Piazza del Plebiscito with the church of San Francesco di Paola.
He continued to author works on both hydraulics and architecture including proposals for straightening the River Topino in Umbria and designs for a bridge over the Tiber at Città di Castello.