Studied in Roma with G. Battaglini, E. Beltrami and L. Cremona. Graduated in 1875. Taught in Bologna (since 1879), Pavia (since 1880) then in Pisa (since 1881). He was correspondent of the Accademia Nazionale dei Lincei.

De Paolis, with Caporali, Veronese and Guccia belongs to the first generation of Cremona 's students and contributed very much to the creation of The Italian school of algebraic geometry.

Students: E. Ciani, F. Enriques, M. Pieri.

Main commemorations: C. Segre, Rend. del Circolo Mat. di Palermo , 1892, 208-224.