Fond of music as a boy, he joined a choral society in Kassel and at 16 was chosen to take a small solo part.
Frantz's first role was in the Kassel Staatstheater in 1927, playing Hermann Ortel in a production of Wagner's Die Meistersinger.
Frantz was a guest artist at the Vienna Staatsoper, Semper Oper in Dresden, at La Scala, and Covent Garden.
Recordings are available with him in these roles from the late 1940s to the mid-1950s, including two complete Meistersingers as Sachs, one of them (from 1956) magisterially sung by Frantz and conducted by Rudolf Kempe.
[1] He also left records as Amfortas, Gurnemanz, Friedrich von Telramund, Iago (in German translation), Don Pizarro and Jokanaan, and as bass soloist in Beethoven's 9th Symphony.