From 1871, he studied at the Lycée Henry IV, where the future president Alexandre Millerand was also among the students. Upon graduation in 1881 he enrolled in the École nationale supérieure des Beaux-Arts and entered the studio of Victor Galland. The following year he studied under William Bouguereau and Tony Robert-Fleury at the Académie Julian. He also exhibited for the first time at the Salon des artistes français.
Dinet made his first trip to Bou Saâda by the Ouled Naïl Range in southern Algeria in 1884, with a team of entomologists. The following year he made a second trip on a government scholarship, this time to Laghouat. At that time he painted his first two Algerian pictures: les Terrasses de Laghouat and l’Oued M’Sila après l’orage.