Marie-Lucie Nessi, born in Paris in 1910, was the elder of two children from the marriage of André Nessi, a Swiss citizen from Locarno, and Hélène Koehne, born in Seesen in the Harz mountains of Germany.
When she had completed high school, Marie-Lucie, then 16 years old, convinced her parents to allow her to attend drawing classes.
After nearly two years of studying plaster antiquities, Marie-Lucie completed her training in the ateliers of Billoul and André Lhote, at the Académie de La Grande Chaumière and the Ecole des Beaux-Arts.
With her fellow students she spent many evenings in the company of Jacques Hélion, Kisling or Foujita, whom they used to meet in the cafés of Montparnasse.
On holiday in Ouistreham, on the north coast of France near Le Havre, Marie-Lucie Nessi met Jean Valtat, only son of Louis Valtat. They were married on 5 April 1932.
Although her father-in-law Louis Valtat, encouraged her, Marie-Lucie Valtat hardly found time to paint, as she had to assist her husband, now Doctor Jean Valtat.
Up till the declaration of war in 1939, Marie-Lucie and Jean used to take their summer holidays in an old second-hand Amilcar, touring most of the countries of Europe. Marie-Lucie brought back numerous watercolours
Marie-Lucie brought Caroline into the world in September 1940, Elisabeth in September 1942, and, as Jean really wanted a son, in August 1944 they were followed by Louis-André.
Since Dr. Valtat never had any other children, Caroline, Elisabeth and Louis-André are the only descendants of the painter Louis Valtat.
In 1948, Jean Valtat, who had formed other attachments that drew him away from the family circle, decided on a complete and definitive break. He obtained a divorce in 1949, and henceforth Marie-Lucie and his children no longer existed for him.
Obliged to look after the children's needs, Marie-Lucie Nessi started toproduce ceramics, hoping to turn her artistic talents to profit.
From 1958, thanks to the assistance of her mother-in-law Suzanne Valtat, who remained firmly attached to her, Nessi abandoned ceramics and at last gave herself entirely to painting.