France's Communist party has undergone a revolution and dropped the hammer and sickle from its membership cards.

The party (PCF) is replacing the communist emblem of peasants and the proletariat with a five-pointed star representing the European Left, a loose alliance of far-left parties, including France's Left Front. The move, announced at the party's 36th congress, which closed on Sunday, has angered traditionalists.

"Everyone in the party is shocked," Emmanuel Dang Tran, the party's Paris secretary told France Info radio. "The PCF is allowing itself and its values to be swallowed up by another organisation."

He said the hammer and sickle represented "a historic element in resistance against the politics of capitalism for the working class of this country", and accused the party leadership of selling out to a form of social democracy made up of "Greens, socialists, Trotskyists and I don't know who else".

Pierre Laurent, PCF national secretary, defended the decision to abandon the symbol, saying it no longer represented present-day realities.

"We want to turn towards the future," he told LCI radio. "It's an established and revered symbol that continues to be used in all of our demonstrations, but it doesn't illustrate the reality of who we are today. It isn't so relevant to a new generation of communists."

The PCF was founded in 1920 and forged a solid power base during the Nazi occupation of the second world war, when its influence spread through the French resistance. But the popularity of the party, which once boasted ministers in several Socialist administrations, has waned in recent years. It is still France's largest leftwing party in terms of membership, but failed to put up a candidate in the presidential election last year, in which it supported Jean-Luc Mélenchon of the Left Front. He took 11% of the vote with the PCF support.

Today the PCF has 10 MPs after gaining 6.9% of the national vote in the 2012 general election. At the height of its influence the party had 28% of the vote and boasted 182 MPs.

The hammer represents the industrial proletariat and the sickle the agricultural labourers or peasants.