Marcusohn began working in the marine biology laboratory of
Édouard Chatton in
Banyuls-sur-Mer, but by September had decided to return to Paris. Once there, she contacted the Romanian affiliates of the
French Communist Party and reconnected with the communist movement. Taking in mathematics students, she worked as a tutor and was eventually offered a post with to translate journal articles to French for researchers at the
Caisse nationale de la recherche scientifique, forerunner to the
French National Center for Scientific Research. She participated in the 1940 demonstrations to protest the arrest of
Paul Langevin and was arrested but quickly released. The anti-Semitic laws threatened the Jewish community in France with destitution, and the burden of poverty fell especially hard on women, and the all more so on immigrant Jewish women. In France, there were two terms for Jews; namely the
les Israélites to describe Jews who had embraced the French language and culture, which was a respectful and polite term, and
les Juifs for those Jews who were seen as having failed to properly embrace the French language and culture, which had derogatory connotations. French Jews were usually described politely as
Israélites while the more derogatory term
les Juifs was reserved for Jewish immigrants, especially from Eastern Europe. The popular image in France at the time of Jewish immigrants from Eastern Europe was of a mass of illegal immigrants who lived in poverty, refused to assimilate and engaged in criminality; the fact that the number of Eastern European immigrants, and even more so of illegal immigrants was greatly exaggerated led to the perception that this was a major social problem. Marcusohn spoke fluent French, but as a stateless Jew from Romania, she was considered to be more of a
Juif than an
Israélite In 1941, Marcusohn joined the Organisation Spéciale—Main-d'Œuvre Immigrée (OS-MOI), the armed group of the
Immigrant Labor Force, using the name Monique as a disguise. She was recruited into underground work by
Boris Holban. She lost her translating job in 1942 and went to work full time, spying for the FTP-MOI. From the summer of 1942 onward, it was widely understood within the French Jewish community that the "Final Solution to the Jewish Question" was not deportation to some vague utopian Jewish homeland in Eastern Europe as the Nazis were promising, but rather genocide, which gave a major impetus to Jewish resistance. Marchusohn recalled that once it was understood that the threat was now an existential one of extermination that many Jews embraced resistance as the issue was one of survival. In 1942 when the OS-MOI merged with two other groups to form the
Francs-Tireurs et Partisans—Main-d'Œuvre Immigrée (FTP-MOI), Marcusohn changed her name again, to Cristina Luca, and became and intelligence officer in the resistance. As the intelligence chief, she selected targets for resistance attacks and collected as much information as possible about the targets. The intelligence branch of the FTP-MOI was a largely female-dominated section, which reflected the prevailing assumptions that women were better suited for intelligence work while men were better suited for action. With the knowledge of her professors, Luca funneled stolen chemicals from the biology laboratory at the Sorbonne to the partisans. Between January-June 1943, the FTP-MOI staged 93 actions in Paris. In the first six months of 1943, the FTP-MOI were responsible for 14 train derailments, 34 acts of arson or bombings of buildings, and 43 assassinations in Paris. The FTP-MOI was regarded as an elite group within the FTP that was always assigned the most dangerous missions, which was seen as an honor. She specialized in constructing Molotov cocktails, and as the intelligence chief of the FTP-MOI she played a key role in the investigation to find the informer who betrayed
Missak Manouchian and his group in November 1943. Ultimately, her investigation exposed as the informer as Joseph Davidowicz, the political commissar to the
groupe Manouchian, who was promptly killed. In 1944, she was assigned to combat duty for the entire north of France and participated in several partisan attacks. During the
liberation of Paris between 19-25 August 1944, she took part in the revolt. Together with her fellow Romanian communists Holban,
Gheorghe Vasilichi and Ion Marinescu, she led a group that seized the Romanian consulate and the Romanian tourist office in Paris, which was announced at the time as the first step towards the overthrow of the regime of the prime minister, Marshal
Ion Antonescu. After the liberation, she joined the French Army as a lieutenant. At the end of the war, Luca returned to Romania in March 1945. Between 1945 and 1947, she worked in the Ministry of Information and then went to
Belgrade,
Yugoslavia, where she worked at the Romanian embassy as a press-attaché for a year. During her time in Belgrade, she was a friend of
Milovan Djilas, who at the time served as the vice-president of Yugoslavia and was Marshal Tito's right-hand man. Because of the
Tito–Stalin Split, Luca was recalled to Romania and began working in the Ministry of Foreign Affairs, in charge of the press department. In 1949, she married Mihail Boico (born Rosner), a military officer in command of troops on the border. Shortly after the marriage, Stalin began targeting veterans of the
Spanish Civil War and those who had been involved in the French Resistance, placing both Boico and her husband, who was known as Bibi, under suspicion. Besides for having served in the French Resistance, Boico's unwillingness to denounce Tito and her friendship with Djilas placed her under suspicion as a "Titoist"; only her friendship with the Foreign Minister
Anna Pauker kept her safe from the
Securitate. Pauker's downfall removed her principle patron and protector from within the PCR. Boico was dismissed from her job in June, 1952 and Bibi was purged from his position in the Interior Ministry that same fall. Boico was assigned to a minor position in the
Grigore Antipa National Museum of Natural History. Disillusioned by the party, after 1956, Boico no longer participated in political activities, concentrating instead on her work in history and science. In the 1960s, she began working as the editor of the Scientific Publishing House and later taught courses on
Marxism at the
Politehnica University of Bucharest. Publishing a few book introductions and journal articles, she increasingly found herself at odds with the regime of
Nicolae Ceaușescu. By the 1970s, she considered Ceausescu's regime to be "fascist" as she was disgusted by the anti-intellecualism of the Ceausescu regime. The American scholar Brett Bowles noted that the crucial role played by women in the Resistance has tended to be overlooked, giving the example of the 1985 French documentary
Des terroristes à la retraite (
Terrorists in Retirement) by Mosco Boucault about the FTP-MOI. Bowles noted that in the film, there was almost no mention of the women who served in the FTP-MOI and Boico, despite her key role as the FTP-MOI intelligence chief, was mentioned only once in passing. Buico was not interviewed for
Des terroristes à la retraite; indeed the only woman interviewed in the film was
Mélinée Manouchian and the interviews with her the focus was mostly on being the wife of
Missak Manouchian instead of her role as a
résistante. In 1987, she left Romania to visit her children in Paris and chose not to return. She began publishing again in France and wrote such works as
Les Hommes qui ont porté Ceaușescu au pouvoir, which has been called by
Vladimir Tismăneanu "the most comprehensive and illuminating analysis" of the rise of Ceaușescu and
Gheorghe Gheorghiu-Dej to the leadership of the Romanian Communist Party. Her major concern in the last years of her life was writing about the Holocaust in Romania and to rebut the attempts, which had started under the Ceaușescu regime in the 1970s, to portray Antonescu as a well meaning, but misguided Romanian patriot who was opposed to the Holocaust. She often advised the Holocaust Memorial Museum in Washington D.C about the subject. At the time of her death she was writing a memoir entitled
Histoire d’une famille au XXème siècle Souvenirs et réflexions. ==Death and legacy==