In 1741 he entered the studio of Jacques Soufflot, his first teacher, then went to Paris to the Académie Royale d'Architecture. In 1746 he obtained the patent as a student architect of the French Academy in Rome, where he moved, and in 1753 the position of first architect of the Bourbon court in Parma. In this period the city experienced a happy period, thanks also to the figure of the minister Du Tillot who was often associated with the name of Petitot, who became the architect of numerous projects commissioned by him. His interventions began in 1753 in Colorno with the hunting lodge commissioned by Don Filippo and with two apartments in the Palazzo Ducale, where he created the Great Hall and rebuilds the staircase towards the garden. From 1754 he worked at the Ducal Garden in Parma, designing some vases that Boudard later sculpted. The style adopted by the Petitot is neither whimsical nor too sophisticated, between the functional and the symbolic, according to a moderately reformist program that combines the Hellenistic line with a new taste for design. In 1767, he carried out the renovation project for the Palazzo del Giardino, raising the wings of the building and mezzanine level and expanding the side areas, while inside he obtained new proportions by redistributing the spaces. In 1759 Du Tillot decided to transform the Farnese Stradone into Stradone Borbone, on the model of the boulevards of Paris, Lyon and Toulouse, to recover the afferent streets, favoring their economic and social recovery. At the poles of the Stradone there should have been the Bourbon Column and the Casino del Caffè, a social meeting place with a panoramic function.
The list of works that Petitot realizes or only designs would be long, there is a collection of a series of etchings published around 1759 where you can admire the great personality of the artist also as an illustrator.