Yes, Art of Erebus is definitely a goth band because most of their albums belong to the Gothic Rock and Darkwave genres, which are among the core subgenres of goth music. Albums like Negative White, Icon In Eyes, and An Open Case Of Parousia are examples of their goth sound.
Some of the other goth artists that are similar to them are Pretentious, Moi and Funhouse.
Art of Erebus is located in France, active in 2001 — present. You can find more information about Art of Erebus on their GothDB band page.