After studying piano and flute at the CNR in Boulogne-Billancourt and Paris, Alphonse Cemin attended the CNSM in Paris, where he took classes in analysis, piano accompaniment, chamber music, melody and lieder. He is one of the founders of the ensemble Le Balcon, and takes an active part in all its projects, as pianist, conductor, artistic advisor or musical director.

Recent engagements include La Cenerentola (Rossini) at the Théâtre des Champs Elysées and the Opéra de Rouen, Iphigénie en Tauride (Gluck) at the Opéra de Nancy. Alphonse’s 2023/24 season will open with I Puritani (Bellini) at the Olympia Maria Callas Theatre in Athens.

Other major productions include Les Indes galantes (Rameau) and Tomás Bordalejo's Bureau 470 at the Teatro Colón in Buenos Aires, George Benjamin's Into The Little Hill at the Théâtre de l'Athénée and the Opéra de Lille, and Michaël Levinas' La Métamorphose at the Festival Musica.

Alphonse has assisted conductors such as Maxime Pascal, Raphaël Pichon, Esa-Pekka Salonen, Kent Nagano, George Benjamin, Marc Minkowski, Daniel Harding, Pablo Heras-Casado, Marc-André Dalbavie and has worked at the Salzburger Festspiele, the Festival d'Aix-en-Provence, the Munich Opera, the Capitole de Toulouse and the Opéra Comique.

As a pianist, Alphonse regularly performs in recital with Julie Fuchs, with whom he records early melodies by Mahler and Debussy, as well as with singers such as Damien Pass, Jenny Daviet, Stanislas de Barbeyrac, Marianne Crebassa, Léa Trommenschlager and Nahuel di Pierro. He also plays with chamber music partners (Jean-Guihen Queyras, Tabea Zimmermann, the Von Kuijk and Zaïde quartets...) and orchestras and ensembles (Ensemble intercontemporain, Mahler Chamber Orchestra...).

Alphonse Cemin is the musical director of the Lundis Musicaux at the Théâtre de l'Athénée, where Dame Felicity Lott, Christoph Prégardien, Sandrine Piau, Nahuel Di Pierro, Malcolm Martineau, Michael Spyres, Dorothea Röschmann, Julia Kleiter, Julius Drake have performed.

In 2010 Alphonse was the HSBC laureate pianist of the academy of the Aix-en-Provence festival and in 2013 he received the interpretation prize of the Stockhausen Kurse Kürten. In 2017 he received the Gabriel Dussurget Prize of the Aix-en-Provence Festival.