Spanish orchestra conductor, composer, and musical critic. He was born in Madrid on July of 1876 in León Street. He was the son of a French father and a Spanish mother. He acquired the doctorate in Philosophy and Literature at the Central University of Madrid, and before that he acquired a bachelor's degree at the Cardenal Cisneros Institute of Madrid. During his stay in Germany, where he was educated as a musician, he was taught by Max Reger, Wolff Ferrari and Ludwig Thuille, as well as Gustav Mahler. He was appointed conductor of the Tonkünstler of Munich, succeeding Weingartner, an orchestra consisting of seventy five professors with which he went on a tour around Spain, Portugal, and France in 1910. Among his repertoire, aside from César Franck, Paul Dukas and Richard Strauss, he made known the symphonic music by Reger, Gustav Mahler, and Anton Bruckner. Settled in Paris in 1912, he was in charge of symphonic formations such as Orchestre Lamoureux. Come World War I, he was drafted by the French army. He was greatly known as a conductor in European cities like Paris, Lisbon, Brussels, Kiev, Riga, and Helsinki. Being a master in the international repertoire, he conducted "Cléopâtre" (1914) in Saint Petersburg, Jules Massenet's posthumous opera. He was part of the 1915 season in the Royal Theatre of Madrid, where he presented "Salomé" by Strauss, starring his wife the Russian singer Maria Kuznetsova [Kousnezoff]. In 1916, both of them went on a tour around the United States in cities such as New York and Chicago. Aside from operas like "Manon", "Thaïs", "Aida", "Traviata", "Faust", "Carmen"", "Tosca", and "Cléopâtre", they presented a Spanish music program with the title "La maja española" where Kuznetsova sang and danced pieces by Albéniz, Granados, Serrano, and Valverde, instrumented by Lassalle and with costume designs by Néstor de la Torre. He Came back to Spain after the European War and conducted the Philharmonic of Valencia, the Royal Theatre Orchestra, and the Symphonic Orchestra of Madrid. In Barcelona, he founded La Filarmónica, and later on in Madrid, the Music Palace Orchestra, commonly known as the Lassalle Orchestra. He kept a correspondence with Manuel de Falla from 1925 until 1930. He organized a concert in honour of Falla with works by the composer which took place in the Music Palace of Madrid on November 5, 1927. The Royal Fine Arts Academy of San Fernando proposed, in 1924, his entering the Civil Order of Alfonso XII. In 1931 he was appointed Official of the Crown of Italy. He died on October 10 of 1932 in Madrid.