Cécile Brunschvicg was one of the grandes dames of French feminism during the first half of the twentieth century. She was born into a well-to-do Jewish family of Alsatian provenance in Enghien-les-Bains just north of Paris on July 19, 1877. Her father, Arthur Kahn, was a prominent textile manufacturer who had opted for French citizenship after the Franco-Prussian War of 1870–1871. Although he strenuously opposed her pursuit of higher education, she studied in secret and received her teaching certification in 1894 at the age of seventeen. In 1899, she married the eminent French philosopher Léon Brunschvicg (1869–1944), who taught at the Sorbonne from 1909 until 1940. The couple had four children between 1901 and 1919, one of whom died at the age of eight. Although Cécile Brunschvicg and her husband were married in the rue de la Victoire Synagogue in Paris, they were freethinkers, and there is no evidence that they provided their children with a Jewish education or that they practiced Jewish rituals in their home. At the same time, they never denied their Jewish identity. As one historian comments, "they lived their Jewishness in the style of certain French Jews...:  without disavowal and discreetly" (Pichon).

According to Brunschvicg’s daughter, it was Léon Brunschvicg, who in 1911 became vice president of the newly created Ligue des Électeurs pour le Suffrage des Femmes (League of Voters for Women’s Suffrage), who initially sparked his wife’s involvement with feminism, and especially the suffrage movement, since he believed that without the vote women’s achievements would never be recognized. From 1908 on, Cécile Brunschvicg played a major role in two French feminist organizations. The first was the Conseil National des Femmes Françaises (CNFF; National Council of French Women), a federation founded in 1901. From 1908 until 1913, she headed the labor section of the CNFF, and in this capacity she founded the Réchauds du Midi in Paris, which provided working women with a warm place to congregate and share meals. The second organization was the Union Française pour le Suffrage des Femmes (UFSF; French Union for Women’s Suffrage), which Brunschvicg helped to found in 1909 together with Jeanne Schmahl (1846–1915) and Marguerite de Witt-Schlumberger (1853–1924). This organization was the French branch of the Alliance Internationale pour le Suffrage des Femmes (AISF; International Alliance for Women’s Suffrage), and Brunschvicg served as its first general secretary. La Française, the weekly newspaper of the CNFF, referred to Brunschvicg as “a woman of action of the first order.” It was largely due to her organizational talents that the UFSF grew rapidly into a national organization in the years before World War I. Although the movement began with a mere 300 members in 1909, by 1914 its membership had risen to approximately 14,000 and regional chapters had been established in all but ten departments.

Brunschvicg’s brand of feminism was moderate and non-confrontational; she believed that the best way to achieve feminist goals was through discreet, behind-the-scenes lobbying. She recognized that men and women were different because of biology, and throughout her career she devoted significant attention to improving both prenatal care and children’s health. Despite her emphasis on women’s childbearing role, Brunschvicg never suggested that men and women should live in different spheres. Indeed, she firmly advocated women’s right to work outside the home in any field, including government posts. Above all she believed men and women should have equal political rights. Although her chief demand was women’s suffrage, she also focused on a range of practical reforms, including greater parity in women’s salaries, expanded educational opportunities for women, campaigns against prostitution and alcoholism, and the drive to reform the French civil code, which treated married women as if they were minors with regard to matters such as acquiring a passport or opening a bank account.

Although Brunschvicg was a pacifist, she fervently supported the French war effort during World War I. She shared the patriotic view of the majority of French feminists that “As long as the war continues, the women of the enemy are also the enemy.” She also actively participated in the war effort by organizing lodging and job programs for approximately 25,000 refugees displaced from their homes in northern and eastern France, an activity for which she was named chevalier of the Legion of Honor. In 1917 she persuaded the Ministry of Labor to create the École des Surintendantes d’Usine (School of Factory Superintendents) in Paris—a school intended to train a professional cadre of female social workers who would provide guidance on issues relating to women's health and welfare. This activity reflected Brunschvicg’s interest in reaching out to working-class women and in seeking to professionalize the field of social work.

During the interwar years Brunschvicg emerged as the leading personality in the suffrage movement. In 1924, after the death of Marguerite de Witt-Schlumberger, she assumed the presidency of the UFSF, and in 1926 she took over the editorship of La Française, which was transferred from the CNFF to the UFSF that same year. In 1924, when the Radical Party, France's principal liberal party, for the first time opened its ranks to women, Brunschvicg was among the first women to join, and in 1925 she became one of ten women nominated to the Radical Party’s executive committee. Although most leading Radicals did not support women’s suffrage, fearing that the majority of French women would vote for conservative and clerical political parties, Brunschvicg nevertheless remained convinced that the path to victory resided in cultivating relationships with high-ranking republican politicians. As she explained in the Radical newspaper L’Oeuvre in 1926, women “should not lose sight for an instant of their fundamental duty, little by little to win over the men around them to our ideas.” Under her tutelage, the UFSF continued to grow, and by 1928 it numbered approximately 100,000 members. In 1929, on the 140th anniversary of the Estates General of 1789, Brunschvicg helped organize the États Généraux du Féminisme, complete with cahiers de doléances, or grievances, presented by French women to the nation as a whole.

In the 1930s, Brunschvicg’s campaign on behalf of women’s suffrage seemed to be stalled. Despite repeated votes in favor of women’s suffrage in the Chamber of Deputies, the Senate voted on six occasions against ratifying this decision. As a result, some feminists lost patience with Brunschvicg’s moderate tactics and began to press for greater militancy. Brunschvicg, however, refused to sever her ties to the Radical Party, and in May 1936, when the Popular Front led by Prime Minister Léon Blum (1872–1950) was elected, she was repaid for her loyalty when the Radical Party recommended her to serve as a junior minister in Blum’s cabinet. Blum named a total of three women to junior ministerial posts: Brunschvicg, who served as undersecretary of state for national education; Suzanne Lacore (1910–1960), who became undersecretary of state for the protection of children; and Irène Joliot-Curie (1897–1956), who served as undersecretary of state for scientific research. These were the highest political offices ever held by women under the Third Republic. Although Brunschvicg remained in office only until June 22, 1937, when Blum’s first ministry fell, she scored some notable achievements. She oversaw the opening of 1,700 school canteens, and she introduced improved health and physical education facilities into the public schools. In 1937 she was recognized for her service when she was promoted to officer of the Legion of Honor. Brunschvicg’s decision to participate in Blum’s government, despite his refusal to make women’s suffrage a priority for the Popular Front coalition, again sparked controversy in some feminist circles. As Louise Weiss, another leading feminist of the interwar years, commented, “Three swallows do not make the spring.” Most feminists, however, believed these high-level appointments constituted an important victory in the battle for full equality between the sexes.

Although Brunschvicg had to relinquish her post as president of the UFSF, as well as her editorial duties at La Française, when she assumed her ministerial duties, she continued to engage in other civic activities throughout the 1930s. In 1931 she helped found the Association d’Études Sexologiques (Association of Sexology Studies), a center-left organization aimed at promoting sex education and population control within a liberal and republican framework, as opposed to the right-wing policies of the pro-natalist Alliance Nationale pour l’Accroissement de la Population Française (National Alliance for the Growth of the French Population). In September of 1937 she was named vice president of the Conseil Supérieur de la Protection d'Enfance (High Council for the Protection of Childhood), and in January of 1938 she became vice president of the Conseil Supérieur d'Hygiène Sociale (High Council for Social Hygiene). She was also an outspoken opponent of the conservative and anti-feminist policies of the High Committee on Population, an interministerial committee created in the spring of 1939, which called on women to stay at home in an effort to increase the birth rate and curb rural depopulation.

Although Jewish issues were not generally high on her agenda, Brunschvicg volunteered in 1933 to help deliver assistance to the 25,000 Jewish refugees from Nazi Germany who fled to France that year. In April 1933, at the time of the anti-Jewish boycott in Germany, she launched an appeal in La Française calling on "all Frenchmen of every religion, who are revolted by the Nazis' brutalities and are desirous of bringing some relief to the victims of Hitlerian persecutions," to participate in the refugee relief effort (Pichon). In May of that year, she announced the creation of the Comité d'Entr'aide Sociale (Committee for Mutual Aid) to assist refugees to find lodging. In the spring of 1933, she also became a member of the Comité d'Aide et d'Accueil aux Victimes de l'Antisémitisme en Allemagne (Committee to Assist and Receive the Victims of Antisemitism in Germany), which soon became the Comité National de Secours aux Réfugiés Allemands, Victimes de l'Antisémitisme (National Committee for the Relief of German Refugees, Victims of Antisemitism), the principal Jewish refugee relief committee, which functioned until 1935. Brunschvicg served as head of the Comité National's Commission de Service Sociale et Médicale, and she also served on the Comité Nationale's executive committee.  

Notwithstanding Brunschvicg's obvious sympathy for the plight of the refugees, she shared the views of the Central Consistory, the governing body of French Jewry, in arguing against an overly generous refugee policy. She believed it was imperative that the refugees find work, so as not to become public charges, and she agreed with the leadership of the Comité National that refugees who retained citizenship in East European countries should be compelled to return to those countries rather than being allowed to remain in France. She also shared the views of French Jewish elites in her fierce opposition to Zionism. In an article in La Française, she strongly criticized the French branch of WIZO, the Women’s International Zionist Organization, for advancing the view that Jews had a national as well as a religious identity. For Brunschvicg, French Jews had only one national identity—French.

One final indication of the degree to which Brunschvicg concurred with views held by the consistorial elite was her reticence to address the issue of antisemitism. Despite her consternation about the rise of Nazi and even French antisemitism, she refrained from addressing the issue directly in the pages of La Française, at least until the Kristallnacht pogrom of November 1938.  Her silence on this issue was striking, since she herself was frequently the target of antisemitic attacks. In June 1937, just as she was beginning her ministerial duties, she visited the Jewish community in Palestine prior to the establishment of the State of Israel. "Old Yishuv" refers to the Jewish community prior to 1882; "New Yishuv" to that following 1882.Yishuv’s pavilion at the 1937 World's Fair in Paris. The Libre Parole ran a photo of her at the pavilion with the caption:  "You're at home" (Formaglio, p. 260). Moreover, during a visit to the University of Strasbourg in 1937, antisemitic students smashed doors and set off tear gas canisters and stink bombs, forcing the cancellation of her lecture.

Brunschvicg's pacifism was tested once again in the late 1930s. At the time of the German remilitarization of the Rhineland in 1936, she still believed Franco-German rapprochement was possible. By 1938, however, especially after the Anschluss and the Munich Accords, she no longer believed in the possibility of peace with Nazi Germany. In La Française, where she had resumed her editorial position after leaving her government post, she exhorted her readers to "defend our fatherland and our liberties" (Pichon). She also created a committee named Les Françaises au Service de la Nation (French Women in Service to the Nation), which began to mobilize women to contribute to the civilian defense effort in the event of war.

After the French defeat of June 1940, Brunschvicg and her husband, who lost his position at the Sorbonne due to Vichy's anti-Jewish laws, fled to the unoccupied zone of Vichy France. They first went to the Gers in southwestern France, where they separated from their daughter Adrienne, who joined Charles de Gaulle's Free French movement in London. They lived there until 1941, when they went to Aix-en-Province. With the German invasion of the unoccupied zone of France in November 1942, they went into hiding for fear that they would be pursued as Jews. In 1943 both Cécile and Léon Brunschvicg assumed false names, and they decided to separate for the sake of safety. Léon Brunschvicg, who was ill at the time, went to a rest home in Saint-Hippolyte-du-Fort in the Gard. After his condition deteriorated, he went to the hospital in Aix-les-Bains, where he died in January 1944. Cécile Brunschvicg, who probably obtained false papers from colleagues in the Resistance, remained in Aix-en-Provence, but in early 1944 she went to Valence in the Rhône valley, where she taught at a girls’ school under the name Madame Léger.

In October 1944, after the liberation of Paris, Cécile Brunschvicg returned to Paris, where she reunited with her daughter and granddaughter and her son. She lived with her son in Neuilly-sur-Seine, since the home she and her husband had owned in Paris had been seized by the Nazis and subsequently sold. She immediately began the process of seeking restitution for her property, as well as the family's library, which had been transferred to Germany.  She recovered her home in May 1945, and in 1946 she recovered over 700 volumes from their library.  

Brunschvicg aso resumed her feminist activities immediately upon returning to the Paris region. From 1944 to 1946 she served on various United Nations reconstruction committees, as well as the executive committee of the Fédération Démocratique Internationale des Femmes (FDIF), an international organization founded in Paris in 1945 to work on behalf of women's rights. She also served as honorary president of the Conseil National des Femmes Radicales Socialistes (National Council of Radical Socialist Women), and she headed the French delegation at the AISF congress held in Interlaken, Switzerland, in August 1945. Moreover, in December 1945 she participated in the rebirth of her newspaper, La Francaise, which became a monthly revue, but it survived only until June 1946.

On April 21, 1944, General Charles de Gaulle’s provisional government in Algiers finally issued an ordinance granting women the right to vote, and on April 29, 1945, women participated for the first time in nationwide municipal elections. Brunschvicg was the sole member of the pre-World War I generation of French feminists to survive to witness this victory. She died of cancer shortly afterwards, on October 5, 1946, at the age of 69. A memorial service was held in her honor at the Sorbonne, and the tributes paid to her have been collected in a printed volume. In the year 2000, her private archives, which had been taken from France to Berlin in 1940 and were subsequently transferred from Berlin to Moscow at the end of World War II, were returned to France. Today they are housed at the Centre des Archives du Féminisme at the University of Angers. Streets are named after her in several French towns and cities, including Rennes, Toulouse, and Saint-Denis, and in 2008 a square in the 18th arrondissement of Paris was named after her.  

Although Cécile Brunschvicg is not well remembered today, she was an indefatigable fighter for women's rights. In addition to her work on behalf of women's suffrage, she helped to implement an array of laws dealing with the health and welfare of women and children. Her work also helped to integrate feminism into French public life, and she played an instrumental role in the professionalization of the field of social work.