The French Communist Party (French: Parti communiste français, pronounced [paʁti kɔmynist fʁɑ̃sɛ], PCF) is a communist party in France. The PCF is a member of the Party of the European Left.

The PCF was founded in 1920 by Marxist–Leninist members of the French Section of the Workers' International (SFIO) who supported the Bolsheviks in the 1917 Russian Revolution. It became a member of the Communist International, and followed a Marxist-Leninist line under the leadership of Maurice Thorez. In response to the threat of fascism, the PCF joined the socialist Popular Front which won the 1936 election, but it did not participate in government. During World War II, it was outlawed by the occupying Germans and became a key element of the Resistance. The PCF participated in the provisional government of the Liberation from 1944 to 1947, but for the next 30 years was excluded from government despite consistently winning more than 20 percent of the vote in elections. It fell behind the Socialist Party in the 1970s, though entered government early in François Mitterrand's presidency (1981–1984) and participated in the Plural Left cabinet led by Lionel Jospin (1997–2002).

From 2009, the PCF was a leading member of the Left Front (Front de gauche), alongside Jean-Luc Mélenchon's Left Party (PG). During the 2017 presidential election, the PCF supported Mélenchon's candidature; however, tensions between the PCF and Mélenchon's movement, La France Insoumise, have led the two parties to campaign separately for the general elections. Although its electoral support has declined in recent decades, the PCF retains a strong influence in French politics, especially at the local level. In 2012, the PCF claimed to have had 138,000 members, 70,000 of whom had paid their membership fees.

The French Communist Party (PCF) originated in 1920, when a majority of members resigned from the socialist French Section of the Workers' International (SFIO) party to set up the French Section of the Communist International (SFIC) with Ludovic-Oscar Frossard as its first secretary-general, with the involvement of Ho Chi Minh as one of the notable agitators participating in its creation. The new SFIC defined itself as revolutionary and democratic centralist. The 1920s saw a number of splits within the party over relations with other left-wing parties and over adherence to Comintern's dictates. The party entered the French parliament, but also promoted strike action and opposed colonialism, a position that was isolated in the French political landscape at the time. The Intercolonial Union, created in 1922, brought together activists from the French colonies around demands for political equality (the right to vote) and social equality ("equal pay for equal work"). The communists thus called for fraternization with the Moroccan insurgents during the Rif War (1925–1926) and to the evacuation of Morocco by the French army, they called for an end to the fighting and the independence of French Syria during the Great Syrian Revolt of 1925–1927, and denounced the festivities of the centenary of the colonization of Algeria, organizing in particular a campaign to boycott the Paris Colonial Exposition (1931).

The party was organized around leaders who were mostly from the working class, setting up training and promotion schemes and encouraging the presentation of working-class candidates in elections. The Maurice Thorez, Jacques Duclos and Benoît Frachon team, who had been miners, metalworkers and pastry cooks respectively, had an exceptional longevity and led the French party for almost three decades. The railroad worker Pierre Semard had been secretary general of the party from 1924 to 1929.

Semard sought party unity and alliances with other parties; but leaders including Thorez (party leader from 1930 to 1964) imposed a Marxist-Leninist line from the late 1920s. With the rise of fascism after 1934 the PCF supported the Popular Front, which came to power under Léon Blum in 1936. The party supported the Second Spanish Republic and opposed the 1938 Munich Agreement with Hitler. It was the only political party in France to denounce this agreement.

The party was banned in 1939 by the government of Édouard Daladier as a result of the German–Soviet Non-aggression Pact, due to its membership in the Comintern, which opposed the War (prior to the invasion of the Soviet Union by Nazi Germany). The leadership, threatened with execution, fled abroad. After the German invasion of 1940 the party began to organise opposition to the occupation. Shortly before Germany invaded the Soviet Union the next year, the PCF formed, in May 1941, the National Front movement within the broader Resistance, together with the armed Francs-Tireurs et Partisans (FTP) group. At the same time the PCF began to work with de Gaulle's "Free France" government in exile, and later took part in the National Council of the Resistance (CNR).

By the time the German occupation ended in 1944, the party had become a powerful force in many parts of France. It was among the leading parties in elections in 1945 and 1946, and entered into the governing Tripartite alliance, which pursued social reforms and statism. However, amid concerns within France and abroad over the extent of communist influence, the PCF was excluded from government in May 1947. Under pressure from Moscow, the PCF thereafter distanced itself from other parties and focused on agitation within its trade union base. For the rest of the Fourth Republic period the PCF, led by Thorez and Jacques Duclos, remained politically isolated, still taking a Marxist-Leninist line, though retaining substantial electoral support.