After completing secondary school during the Nazi occupation, Simone was responsible for supporting her family and forced to take work as a typist for a French collaborationist newspaper Les nouveaux temps, run by Jean Luchaire.

[4] During the occupation of France, Signoret mixed with an artistic group of writers and actors who met at the Café de Flore in the Saint-Germain-des-Prés quarter.

By this time, she had developed an interest in acting and was encouraged by her friends, including her lover Daniel Gélin to follow her ambition.

In 1942, she began appearing in bit parts and was able to earn enough money to support her mother and two brothers as her father, who was a French patriot, had fled the country in 1940 to join General De Gaulle in England.

She won further acclaim, including an acting award from the British Film Academy, for her portrayal of another prostitute in Jacques Becker's Casque d'or (1951).

In 1962, Signoret translated Lillian Hellman's play The Little Foxes into French for a production in Paris that ran for six months at the Theatre Sarah-Bernhardt.

[5] Signoret's one attempt at Shakespeare, performing Lady Macbeth with Alec Guinness at the Royal Court Theatre in London in 1966 proved to be ill-advised, with some harsh critics; one referred to her English as "impossibly Gallic".