Biografia   

He was the son of a silk trader. He left Lyon and went to Paris and wanted to become a painter. He studied singing at the Conservatoire National in Paris under the pedagogue Novelli. He made his debut in 1886 at the Opera House in Lüttich as Saint Bris in ‘’Huguenots’’ of G. Meyerbeer. After his appearances at the opera houses of Lille, Toulouse, Hague and Brussels, he joined in 1872 to the Grand Opéra in Paris, where he made his debut as Wilhelm Tell in G. Rossini’s opera of the same name. Through long years he belonged to the most prominent members of this opera house. Especially he was appreciated at the Covent Garden, where he appeared  in the 1879-1881 and 1888-1893 seasons in the parts like the Fliegenden Holländer, Telramund and Hans Sachs.
At the Covent Garden in London he appeared in the following opera premieres:
1881 ‘’Demon’’ (English première) A. Rubinstein
1892 ‘’The Light of Asia’’ Isidore De Lara
1893 ‘’Amy Robsart’’ Isidore De Lara
At the Grand Opéra in Paris he appeared in the following opera premieres:
27.4.1877 ’’Le Roi de Lahore’’ Jules Massenet
7.10.1878 ‘’Polyeucte’’ Charles Gounod
1.4.1881 ‘’Le Tribut de Zamora’’  Charles Gounod
14.4.1882 ‘’Françoise de Rimini’’ Ambroise Thomas
21.3.1890 ‘’Ascanio’’ Camille Saint-Saëns
5.3.1883 ‘’Henri VIII’’ Camille Saint-Saëns
1892 ‘’Samson et Dalila’’ Camille Saint-Saëns
At the Théâtre de la Monnaie in Brussels he appeared in the following opera premiere:
15.7.1884 ‘’Sigurd’’ Ernest Reyer
In 1890 he sang at the Paris Opéra-Comique in a gala performance of ‘’Carmen’’ with Jean de Reszke and Nellie Melba. Then in the 1892-1898 (with interruptions) seasons he was a famed member of the Metropolitan Opera in New York. Here he made debut in January, 1892 in as Nelusco in ‘’L'Africaine’’ of G. Meyerbeer. At the Metropolitan Opera his repertoire included Don Giovanni, the title part in ‘’Hamlet’’ of A. Thomas, Valentin in ‘’Faust’’ of C. Gounod, Escamillo in ‘’Carmen’’, Nevers in ‘’Huguenots’’, Telramund, Hans Sachs and Wolfram in ‘’Tannhäuser’’. Then he returned to France and some years appeared in Paris, but since 1901 devoted himself to teaching and received in 1903 a professorship of the Conservatoire de Paris. Jean Lassale counted as one of the most significant Baritons of his epoch, who was compared many times to his predecessor, the famous Jean-Baptiste Faure. His son Robert Lassalle, became a known tenor, who was trained by his father and J. Isnardon.

Chronology of some appearances (Opera premieres)

London Covent Garden
1881 ‘’Demon’’ (English première) A. Rubinstein
1892 ‘’The Light of Asia’’ Isidore De Lara
1893 ‘’Amy Robsart’’ Isidore De Lara
Paris Grand Opéra
27.4.1877 ’’Le Roi de Lahore’’ Jules Massenet
7.10.1878 ‘’Polyeucte’’ Charles Gounod
1.4.1881 ‘’Le Tribut de Zamora’’  Charles Gounod
14.4.1882 ‘’Françoise de Rimini’’ Ambroise Thomas
21.3.1890 ‘’Ascanio’’ Camille Saint-Saëns
5.3.1883 ‘’Henri VIII’’ Camille Saint-Saëns
1892 ‘’Samson et Dalila’’ Camille Saint-Saëns
Brussels Théâtre de la Monnaie
15.7.1884 ‘’Sigurd’’ Ernest Reyer
fonte: forgottenoperasingers.blogspot.it