BOSTON (AP) — Call them songs in the key of "oui." The Boston Symphony Chamber Players are staging an all-French program Sunday at the New England Conservatory's Jordan Hall. The renowned ensemble will perform 19th- and 20th-century works by Paul Taffanel, Camille Saint-Saens and Jean Francaix. They'll also play a piece by contemporary French composer Eric Tanguy. The Boston Symphony Chamber Players were founded in 1964.