He attended the École Royale d'Architecture de Paris, part of the Académie des Beaux-Arts, a school that was not known for developing original architects.

[2] Hermitte was involved in construction of the Roman Catholic Cathedral of the Sacred Heart of Jesus in Canton (Guangzhou), China, but his role is unclear.

[2] Eudore de Colomban in his biography of Zéphyrin Guillemin, Bishop of Canton, wrote that around 1865 or 1866 a new, 26-year-old architect had arrived, but work on the cathedral was still making little progress.

[4] This included a chapel to mark the place where Saint Francis Xavier had died on Shangchuan Island, southwest of Canton.

[7] The City Hall and Hermitte's other buildings were erected by skilled Hakka stonemasons from Ngwa (Wuhua) in eastern Kwangtung (Guangdong).

La Grandière laid the cornerstone for this building on 23 March 1868, a block of blue granite from Biên Hòa containing a lead coffer that in turn contained newly-minted gold, silver and coin coins of Napoleon III.

[11] Work on the huge Saigon Governor's Palace began in earnest when Hermitte brought in skilled workmen from Canton and Hong Kong.

The site of the Palais du Gouverneur turned out to be waterlogged and the foundations required constant repair to counteract subsidence throughout the building's life.

[4] The Hong Kong City Hall was a Victorian-style building on the edge of Victoria Harbour that was meant to be a hub for both cultural and administrative activities.

The building would also hold a public library that could accommodate 10,000 books and the museum of the South China Branch of the Royal Asiatic Society.

[19] In early 1867 Bishop Guillemin wrote that, "M. Hermitte, our architect, has given us the plan which he wished to donate for St. Francis and one of our missionaries, M. Braud, is presently in place putting it into effect.

There was a slab in the floor that marked the place where Saint Francis Xavier had died, and there were three small wooden altars, two in niches on the north and south sides and one in the apse.

[22] The Saigon Governor's Palace was intended to impress the local people with France's power and wealth.

[14] in 1869 King Norodom of Cambodia entered into a contract with Hermitte and a wealthy Saigon merchant named Wang Tai, whose brickyards were supplying the bricks for the Saigon Governor's Palace, to do the same for Norodom's new palace in Phnom Penh.