Soyer was born in Thiais, and first studied privately with G. Daum, before entering the Conservatoire de Paris at the age of 19.
He made his professional debut at the Théâtre des Champs-Élysées in 1962, creating the role of Mac Creag in Gilbert Bécaud's opera L'opéra d'Aran.
He sang on French Radio in 1964, in Rameau's Hippolyte et Aricie, and made his debut at the Aix-en-Provence Festival in 1965, as Pluton in Monteverdi's L'Orfeo.
The same year he made his debut at the Opéra-Comique, as Colline, in La Bohème, and at the Palais Garnier, as Mephisto in Gounod's Faust.
Other notable roles include; Ferrando in Il trovatore, Procida in Les vêpres siciliennes, Titurel in Parsifal, Rangoni in Boris Godunov, Pope Clement in Benvenuto Cellini, Achis in David et Jonathas, Narbal in Les Troyens, etc.