Madame Ramon Subercaseaux John Singer Sargent (1856-1925)

The picture has something of this: people, music, woman, wear, musician, performance, portrait, opera, theater, dress, costume, model, fashion, singer, girl, retro.
Perhaps it’s a painting of a woman in a white dress sitting at a piano with a bouquet of flowers in front of her and a vase of flowers behind her.