Ceinture rouge

The Ceinture Rouge ("Red Belt") refers to the communes of the Île-de-France that were dominated by the French Communist Party from the 1920s until the 1980s. These communes are those that are traditionally working-class areas whose residents were employed in the heavy and light industries that once dominated the economic landscape of the Petite Couronne (the departments that border Paris) and large population centers in the outer departments of the Île-de-France. 
While the phenomenon is not specific to Paris and can also be seen in Lyon, Turin, Milan or Genoa, for example, "its scale and, most importantly, the length of the communist implantation in these municipalities make it a unique phenomenon in Europe".
The strength of the French Communist Party in these areas also led to this party forming the government at the departmental level in Seine-Saint-Denis from its creation in 1967 up to 2008, when control of the Departmental Council went to the Socialist Party of France.
History.
Beginnings (1920 to 1935).
The idea of a "Red Belt" takes its roots in the 1920s.
At the 1919 municipal elections, "a first red wave let municipal socialism take roots in communes with an industrial and working-class tradition, such as Aubervilliers and Saint-Denis. A year later, these towns voted for the newly created Communist Party," notes historian Emmanuel Bellanger.
The phrase itself was coined in an article written by Paul Vaillant-Couturier, "Paris encircled by the revolutionary proletariat" after the legislative elections of 1924 and the municipal elections of 1925.
However, at that time, the PCF's tactics of “class against class” only allowed it to win nine towns in 1925: it kept Bezons, Bobigny and Villetaneuse, took Saint-Denis from SFIO dissidents, and Clichy, Malakoff, Vitry-sur-Seine, Ivry-sur-Seine, Villejuif from the right.
In the 1929 municipal elections, the PCF won Pierrefitte-sur-Seine from the right, while Alfortville and Bagnolet were lost to the SFIO.
The "golden age" of local-level communism (1935–1981).
Front Populaire.
The PCF stopped using the "Red Belt" as a motto as it engaged in the strategy of the “Front Populaire” alliance for the 1935 municipal elections. The alliance between the PCF and the SFIO captured 26 municipalities. However, it lost its fiefdom of Saint-Denis, as Jacques Doriot, who had been excluded from the communist party in 1934, was reelected.
Thanks to the success of the PCF at the 1935 elections, Georges Marrane, communist mayor of Ivry-sur-Seine, became president of the General Council of the department of Seine in 1936.
The communist party was also successful is the neighbouring Seine-et-Oise department: out of 129 municipalities with a population above 2,500, "red" municipalities rose from 8 to 24 at the 1935 elections: Argenteuil, Aulnay-sous-Bois and Blanc-Mesnil all elect communist mayors. This number rose further to 54 in 1945, the year in which even the very bourgeois city of Versailles had a mayor "close to the communists".
This success can be partially attributed to the housing crisis that brought a large working-class population to the suburbs, where the living conditions were particularly poor. The communist party's agenda, which focused on public investment in housing and healthcare, appeared particularly attractive: 
Aftermath of the second world war.
The Communist party emerged from World War II as a dominant political force:
After the second world war, other parties tried to exploit the PCF's political isolation and reduce its stronghold over the Paris suburbs. A 1947 law introduced the proportional allocation of seats in municipal councils for cities with a population above 9,000 inhabitants. Since the PCF could not form alliances with other political parties, it lost 22 communes in Seine-Banlieue to the SFIO and to Charles De Gaulle's RPF in the 1947 elections.
At the end of the 1950s, the PCF's setbacks on the national stage paradoxically illustrated what Pierre Bellanger calls "the resilience of municipal communism". The first of these setbacks was the 1958 constitutional referendum. Despite the PCF's opposition, it was overwhelmingly approved, with a majority in every single "département" and major city. In the Paris suburbs, Bagnolet was the only "red" city where the "no" was actually ahead. This defeat proved that the PCF was not able to impose its vote, even in its traditional fiefdoms.
Two months later, the PCF was crushed at the 1958 legislatives elections, going from 150 seats to 10. Communist leaders Étienne Fajon, Jacques Duclos and Marie-Claude Vaillant-Couturier lost their seats.
After these two major defeats, the PCF was expected to experience major losses at the 1959 municipal elections. But the opposite happened: revived by the unpopularity of the Pinay-Rueff plan, the PCF won 7 new cities, bringing its total to 31 in Seine-banlieue.
The reinstatement of the majoritarian system from 1959 to 1977 benefited the PCF. In the mid-60's, it formed alliances with the SFIO, which managed to capture 25 of the 39 cities with a population over 30,000 inhabitants.
The strength of the PCF played a central role in the 1964 redistricting of the Ile-de-France region, designed to only leave one General Council to the communists:
This equilibrium functioned until 1977. Despite the considerable progress of the Socialist Party at the National level after the Epinay Congress, voters of the inner suburbs kept favouring municipal communism: there were 46 communist municipalities in the inner suburbs in 1971 - a number that rose to 54 in 1977. In addition, the PCF made new inroads in the outer suburbs, in Poissy, Les Mureaux and Mantes-la-Ville, and confirmed recent wins in cities such as Montereau, Palaiseau or Savigny-sur-Orge. The 1978 legislative elections confirmed that the PCF was the first left-wing party in the Ile-de-France region.
Decline (since 1981).
1977 marked the pinnacle of the Red Belt. Its following decline has many causes: first, the communist party rapidly lost influence at the national level in the 1980s, after forming an alliance with the Socialist Party and joining the socialist government after the 1981 elections. While Jacques Duclos, the communist candidate, had received 21.7% of the national vote in the 1969 presidential election, André Lajoinie only obtained 6.8% in 1988.
In Ile-de-France, the party also failed to adapt to the changing demographics of working-class cities. As historian Romain Ducoulombier notes:
In the National Assembly, the decline started as early as 1981: the party lost half of the seats it held (13 out of 27) - a trend confirmed 5 years later with the loss of 4 more seats. After that, the number remained stable until 2002, when it lost 2 more seats in the aftermath of the dismal results of Robert Hue in the presidential election.
In municipal elections, the decline was slower but inexorable: when a city elected a non-communist mayor, it hardly ever made the journey back. As Philippe Subra notes:
In the (1988–2004) period, the number of cities held by communists in Ile-de-France went from 67, including 51 with a population over 20,000, to 42, of which 32 have a population above 20,000.
The 2014 municipal elections represented a major defeat for the Communist party: in Seine-Saint-Denis, it lost Bobigny, Saint-Ouen, Bagnolet and Blanc-Mesnil, four cities that it had held for decades. In the Yvelines, it was defeated in Achères, the last city it held in the département. But its most significant setback was the loss of Villejuif, a city that had had a communist since 1925 and in which former communist leader Georges Marchais had been elected to the National Assembly. The communist victories in Montreuil and Aubervilliers appeared as a consolation prize.
The 2020 municipal elections confirmed the slow disappearance of the Red Belt: the PCF lost 4 out of 10 cities it held in the département of Val-de-Marne: Villeneuve-Saint-Georges, Choisy-le-Roi, Valenton and Champigny-sur-Marne, but it won back Villejuif. In the département of Seine-Saint-Denis, it lost two of its historical fiefdoms, Saint-Denis and Aubervilliers, but won back Bobigny.
Symbolism and political significance of the Red Belt.
The Red Belt as a "laboratory" of communism.
The idea of a Red Belt around Paris is not only an electoral phenomenon. It constitutes, in the words of Annie Foucault, "a political myth":
As early as the 1920s, the communist party uses these cities as examples of what it could achieve on the national stage. But the image of a "Red Belt" is also used by political opponents to denounce the dangers that communism would represent at the national level. As Emmanuel Bellanger writes:
To avoid demonization, communist mayors actually stayed clear from radical changes when they won a city: while their party was often isolated nationally, communist mayors collaborated with their left- and right-wing colleagues. Jacques Girault thus writes:
Communist cities are used to demonstrate the benefits of the communist platform, with a strong emphasis on social services, collective housing and taxes paid mostly by corporations. These policies are perceived positively, even by people who are not communist sympathizers at the national level:
But this model was largely based on the presence of large factories around Paris, which would bring tax revenues and would need factory workers living nearby. In the 1970s, the deindustrialization of the inner suburbs brought its decline: the Plaine-Saint-Denis, which used to be largest industrial zone in Europe, became an industrial wasteland within years, while Renault-Billancourt closed in 1989: 
The Red Belt as a springboard for national communist figures.
These constituencies also provide a springboard to the national stage, as well as safe seats for the leadership of the communist party:
Effects on the urban landscape.
Because of the emphasis communist cities placed on affordable working-class housing, Red belt cities often present "a certain type of urban landscape, with an alternation of modest individual homes and low-rent collective housing projects, the presence of industrial activities and a particular collective culture and sociability".
One ingredient of this collective culture and sociability is the creation of cultural institutions and, in particular, large public theaters:
These theaters and cultural institutions are the direct result of the communist municipalities' strategy, in the 1960s and 1970s, to use public commissions to create buildings that represent the idea of architectural modernity: another example is provided by the concrete administrative center of the communist municipality of Pantin, built in 1970 by Jacques Kalisz, a communist architect. In other cities, André Lurçat, Paul Chemetov, Serge Magnien and other modernist architects close to the PCF renovated the suburbs. Georges Valbon, mayor of Bobigny, accepted the renovation of the town according to the standards of slab urbanism: he notably entrusted Oscar Niemeyer with the creation of the departmental labor exchange.
As these suburban cities broke with their communist past, newly elected mayors often tried to mark the change by renaming streets that referred to communist leaders. In Argenteuil, Frédéric Says notes: 
List of cities that have been part of the "Red Belt".
Based on the départements created in 1964.
The cities whose name is followed by an asterisk have a mayor from the PCF or Front de Gauche since the 2014 municipal elections. Those followed by 2 asterisks (**) have a left-wing majority that includes most of the time the PCF, but which mayor neither belongs to the PCF nor the Front de Gauche.