John Singer Sargent -- American painter
She is the mother-in-law to John S. Sargent's little sister Violet (Sargent) Ormond. Violet had married Marie Marguerite's only child Francis Ormond in 1891 and from the marriage they would give her six grandchildren.
According to Richard Ormond (great grandson to Marie Marguerite and great nephew to John Singer Sargent) Marie Marguerite Renet Ormond was quite the matriarch and was instrumental in raising her two oldest granddaughters herself -- refusing to give them up when the ever nomadic parents -- Violet and Francis -- moved to London. If this dating is correct Marie Marguerite would be 61 years old in Sargent's drawing.