He studied natural sciences at the Universities of Bonn, Berlin and Freiburg, obtaining his doctorate in 1895 with a thesis on the ciliate- Bursaria truncatella titled Bursaria truncatella unter Berücksichtigung anderer Heterotrichen und der Vorticellinen.

[1] Along with other scientists, he participated in the "1898–99 German Deep-Sea Expedition" aboard the steamer Valdivia under the leadership of Carl Chun (1852–1914).

Brauer distinguished himself in the field of deep-sea ichthyology, based largely on his experiences from the 1898–99 "Valdivia Expedition" as well as in his subsequent analyses of species collected on the journey.

[4] He was the author of Die Süßwasserfauna Deutschlands, a work on freshwater fauna of Germany that was published in nineteen parts from 1909 to 1912.

[6] In 1896 herpetologist Oskar Boettger (1844–1910) named the lizard species Janetaescincus braueri (Brauer's burrowing skink) in his honour.