Guillaume was born in Rennes, France. He started training at the Académie Julian in Paris, where he spent 1889 through 1895. He had many teachers there, including Gabriel Ferrier, William-Adolphe Bouguereau and Tony Robert-Fleury.
In addition to his training in the academic style, much of Seignac's work displayed classical themes and style, for example, his use of diaphanous drapery covering a woman's body is reminiscent of classical style, in particular the sculptor Phidias.




