Alteau was born in Liège, and began making comics while still very young. Already at age 10, he met comic artist Paul Deliège, who trained hem in his first efforts. He had his first publication with Deliège in Spirou magazine at age 14, and at 16, he was in Paris drawing for several independent punk, reggae and ska groups. He eventually became the assistant of Frank Margerin on the series 'Manu', and contributed to a variety of magazines, including Spirou ('Zic Boutik', 'Poulets de Kentucky'), Le Journal de Mickey, Picsou and Grodada.
He became the regular colorist of Florence Cestac's work, including the series 'Les Ados' and 'Les Débloks'. He released his first comic book in 1997, in commission of UNESCO. Much later, in 2006, he launched a new series with writer Jim, in which the authors imagine the youth of great political figures. It started with 'Le P'tit Chirac', and was followed by three books about Sarkozy.
Alteau joined the team of 'Vie de merde' at Éditions Jungle, and illustrated the sixth and tenth installments in this series. He also contributed to Jungle's humor series 'Le gros livre des blagues', that contains collections of jokes written by children and drawn by comic artists Alteau and Curd Ridel.
He made a graphic contribution to the book 'Françaises, Français, Belges, Belges, Lecteur Chéri, Mon Amour' (Jungle!, 2005), in which comic artists illustrated short stories by comedian Pierre Desproges.