He served as the ecclesiastical architect of the Roman Catholic Archdiocese of Algiers from 1855 to 1870.

[1] Fromageau served as the ecclesiastial architect of the Roman Catholic Archdiocese of Algiers from 1855 to 1870.

[2] He also designed Notre Dame d'Afrique in the Neo Byzantine architectural style.

[1][2][3] Additionally, he designed a seminary in Kouba and another one in Saint-Eugène, two suburbs of Algiers.

[1] Upon his return to France, Fromageau designed the Roman Catholic church in Saint-Jouin-de-Milly.