Some Socialists say those failings still leave them an opening. The optimists cast the party’s move from Paris’s Seventh Arrondissement a year ago because of financial constraints not as a retreat but as a chance at rebirth — an opportunity to shed their image of being limousine liberals and the “gauche caviar.”

Their new home in Ivry-sur-Seine, an eastern, working-class suburb, gentrifying in pockets, which remains a stronghold of the French Communist Party, represented that aspiration, they say.

“The symbol we sought was to be able to say that we are, once again, among those we’re called to represent,” said Olivier Faure, the party’s secretary general, adding that the party’s former supporters had “sometimes felt abandoned once we were in power.”

In an interview in his glass-walled office, Mr. Faure, 51, unfurled a map to bring back his party to relevance. He said his party would focus on the destructive effects of globalization and free markets on people and the environment.

Just as his party had represented workers in the past, it needed to address the needs of those toiling in an “Uberized economy,” who “in reality are slaves of algorithms and management methods that are extremely brutal.”

Like all parties in France, from the extreme left to the extreme right, the Socialists were keenly aware of the rising importance of the environment as an electoral issue. To Mr. Faure, the biggest victims of climate change were globalization’s losers, and his party must make it its mission to defend them.