According to Le Monde, Bernstein was known particularly as one of the pioneers of early music recording in France, issuing important discs by harpsichordist Blandine Verlet, pianist Paul Badura-Skoda (playing antique fortepianos), lutenist Hopkinson Smith and others; he produced the complete organ works of Bach as played by Michel Chapuis and the earliest discs of Philippe Herreweghe and his Collegium Vocale, the period-instrument Quatuor MosaÇques, Rinaldo Alessandrini and Concerto Italiano, and others.
Bernstein's best-known recordings were on his third label, Astr_e, founded in 1975. The firm and its producer managed to lure viola da gamba virtuoso Jordi Savall and his ensemble, Hesprion XX (now XXI), away from EMI Classics. Savall made his first recordings of the great French Baroque repertoire for viol by Marin Marais and Fran‹ois Couperin for Astr_e, setting in motion the trend that led to Savall's soundtrack for the hit 1991 movie Tous les matins du monde. Unfortunately, according to Le Monde, Bernstein got no piece of that film's financial success: shortly before the release of Tous les matins and its bestselling soundtrack disc, financial difficulties forced him to sell Astr_e to another label, Auvidis. (The combined label was subsequently purchased by NaÇve Classique, which remains in possession of the Astr_e catalogue today.)
In 1992, Bernstein moved to Nantes and started yet another label from scratch, Arcana. While Savall went on to launch his own label (Alia Vox) and most of Astr_e's artists remained with NaÇve, Arcana recorded a new generation of talented early music specialists: the ensemble Ars Antiqua Austria, the Festetics Quartet (which has recorded the complete Haydn string quartets on period instruments for Arcana) and Dialogos. Bernstein and his label even helped stretch the boundaries of the "early music" movement, releasing the first Debussy recording on period instruments (of chamber music, played by members of the Kuijken family) and beginning a series of that composer's complete piano music on late 19th- and early 20th-century Erard pianos.
In his remembrance of Bernstein for Le Monde, the esteemed French critic Renaud Machart writes of Arcana, "The discs come out in dribs and drabs (an average of one per month, no more), the repertoire is rare, carefully presented with multilingual booklets and [the scholarship and performances are] musicologically impeccable."
