In Paris, Lacombe initially established himself as a virtuoso pianist, increasingly dedicating himself to composition and music criticism. (His essays were partly reprinted in a posthumous collection, Philosophie et musique (1896).)
Lacombe's first published works include a piano quintet, a trio, and some piano pieces. He wrote a number of dramatic symphonies with soloist and choir, and his cantata, Sapho, was performed at the famous Paris Exposition Universelle (1878).
He wrote several operas, but only two were performed in his lifetime. La madone was a completely modern composition with musical continuity through each act, elaborate orchestration, and only a small amount of spoken dialogue. However, the opening night response was described as lukewarm. Madame Boniface, a two-act comic piece, was performed in 1883, late in his life. Perhaps his finest work is Winkelried (1892), a four-act grand opera that premiered posthumously. Steven Huebner, writing in Grove, states 'musically the score is worth more recognition than it has received. It betrays none of the influence of Gounod seen in so many French operas of the period. Though it is conservative in form, the orchestration and harmonic style are rich (...) Stirring homorhythmic choruses make Winkelried a fine vehicle for Swiss patriotic sentiment.'