Greece’s Syriza has maintained a steady lead in the polls ahead of Sunday's legislative elections.
The left-wing party, running on an anti-austerity platform, has the support of the hard left in France, which organised the support rally on Monday night.
Joining Jean-Luc Mélenchon’s Left Party and the Communist Party were members of the French Green and Socialist parties, revealing a rift in the French left over the issue of economic austerity.
"What we are facing in Greece is not an isolated case," said George Kotrougalos, an MEP with Syriza, who was representing the party at the rally. "Of course we have been victimised by austerity policies but, if you look throughout Europe, all European peoples are victims of the same policies."
He says the rise in power of the French far right is a direct result of the French government’s insistence on following these policies.
"This is real a dilemma for the European society in the future: how are they going to express their anger against these austerity policies? With parties like that of Mrs [Marine] Le Pen [the Front National], with xenophobia and racism? Or with parties like Syriza, that wants rights, freedom and liberties?"
Attendees of the rally came to support Syriza, a Greek party, because they identify with the issues in France.
"All Europeans are concerned by austerity," said Lara, a student who voted for François Hollande in the 2012 presidential election and supported the Socialists but has been disappointed.
Bruno, an activist with the Left Front grouping of parties, says he feels the impact of austerity at his university in Paris.
"We have fewer professors; the buildings are falling apart," he explains. Austerity is not hitting France as hard as Greece, "but we are fighting against it also in France."
Syriza has its roots as a radical, anti-establishment grouping of Maoists, Trotskyists and anti-capitalist activists. But it has won mainstream support by promising social spending, raising the minimum wage and other anti-austerity measures.
MEP George Kotrougalos says Syriza has emerged as the only choice in Sunday's election "because the Socialists in Greece have been so much identified with these policies of austerity and social misery".
Over the last few years, Syriza leader Alexis Tsipras has become pragmatic, toning down anti-European rhetoric among other moves.
Though he still has to contend with about a third of his party that advocates exiting the euro and going back to the drachma.
This realism has made him palatable for Socialists like Liem Hoang-Ngoc, a former French Socialist MEP.
"Tsipras want to stay inside the euro and wants to renegotiate [Greece's] debt," he said. "He put on the table a very realistic plan."
Syriza has attracted former members of Greece's Socialist Pasok party, which has tanked in the polls.
Hoang-Ngoc says France should watch carefully, as part of the ruling Socialist Party is unhappy with Hollande's economic policies.
"This is an interesting experiment," he said. "If some Socialists within Syriza can build a new, strong government with a new strategy, it could show the way for other Socialists and other radical leftists in Europe, maybe even in France."
The Syriza support rally in Paris attracted speakers from the organisers, the Communist and Left Parties, which share a direct political affinity with the Greek party. But it also drew a few Socialist lawmakers and Green party members.
Communist Party chief Pierre Laurent says left-wing forces in Europe are supporting Syriza because they're hoping for a change and "for a people to rise up, and for a government to say, 'Enough with austerity'.”
"If Syriza wins in Greece, it's an opportunity for the French left and an opportunity to reignite the European debate," he says.
Former Green party leader Cécile Duflot, who quit the government last year, also attended the rally and said she is open to working with anyone who takes to heart ecological concerns.
"We Greens have been working with the Left Front for a long time and with the Socialists," she said. "What is important for us is their policies."
At issue is not a political coalition, she said. "The real subject is what projects exist for the European people."
And the project that is dominant today "is crushing us, even suffocating us," she said.
At the end of the rally, whether due to time constraints or political reasons, Duflot left right before the participants gathered on stage to sing the left-wing anthem, the Internationale.