This is a painting by the famous French Impressionist painter Camille Pissarro (1830-1903), and the subject is his daughter Jeanne (known as Cocotte), one of his seven children, and the only girl. Perhaps of interest to UK readers, Pissarro lived in the outskirts of London for a number of years -- not far from where my daughter and family live now. He seems to have liked it there and came back several times for the rest of his life.
A sad bit of information from Wiki:
When Pissarro returned to his home in France after the war, he discovered that of the 1,500 paintings he had done over 20 years, which he was forced to leave behind when he moved to London, only 40 remained. The rest had been damaged or destroyed by the soldiers, who often used them as floor mats outside in the mud to keep their boots clean. It is assumed that many of those lost were done in the Impressionist style he was then developing, thereby "documenting the birth of Impressionism."
Rather glad I wasn't there to witness his reaction to this!