France's Socialist Party on Friday suspended talks aimed at uniting centre-left and hard-left parties ahead of parliamentary elections in June, in a sign of the hurdles the left faces as it tries to challenge newly re-elected President Emmanuel Macron.
Macron will need a majority in parliament to implement his policies. In recent French legislative ballots, the president's party has always secured a majority.
But parties to the left and right hope they can win enough lawmakers for things to be different this time, even if some early opinion polls point to Macron securing a majority.
Hard-left politician Jean-Luc Melenchon, who came third in the first round of France's presidential election on April 10 with nearly 22% of the vote, is seeking to unite the fragmented left, including the Greens, under his banner.
But the Socialists, who once ruled France and are now fighting for survival after winning less than 2% on April 10, said that can only happen if his France Insoumise (France Unbowed) party treats them better in the negotiations.
"We wish to reach an agreement between all left-wing parties and the ecologists," Socialist leader Olivier Faure said in an internal message to party members seen by Reuters.
"But to manage it, it will require a true shared logic. We have to break from any hegemonic logic and accept plurality. At this stage we have no guarantee of that," Faure added.
Some of Melenchon's policies, in particular his opposition to France's NATO membership and his criticism of the European Union, are difficult for the staunchly pro-European Socialist Party to accept.
And the two parties have been at loggerheads for years.
If Macron's centrist La Republique en Marche (LaRem) party fails to win a majority in the legislative ballot, he would have little choice but to name a prime minister from another party.
This would usher in what has traditionally been a tense period of "cohabitation" during which presidential powers are severely curbed.
Macron won a fresh five-year presidential term after beating far-right challenger Marine Le Pen in last Sunday's runoff vote.
France will hold parliamentary elections on June 12 and 19.
(Reporting by Elizabeth Pineau; Writing by Juliette Jabkhiro; Editing by Ingrid Melander and Gareth Jones)