Allies of French President Francois Hollande have mobilised in hopes of securing a crushing parliamentary majority for the Socialists that could bolster him in talks on how to save the embattled euro currency and revive Europe's economic fortunes.
Leftists dominated the first round of legislative elections, and Socialist leaders are calling for a final push of party unity ahead of Sunday's decisive second round of voting for seats in the National Assembly.
Mr Hollande, who was elected last month, wants his political kin to control the powerful lower house of Parliament for the next five years so he can move forward with plans to strengthen the state's role in the economy, create thousands of teaching jobs and tackle high youth joblessness.
Final results released on Monday from nationwide balloting on Sunday showed the Socialists and their allies on the left winning at least 46% of the vote.
The main conservative bloc, led by former President Nicolas Sarkozy's UMP party, had at least 34%. The unaligned far-right National Front won 13.6%, remaining a wild card for the June 17 second round. Tiny parties drew the rest.
"(Voters) have clearly expressed their desire to give Francois Hollande the means to act during this five-year term," Socialist boss Martine Aubry said. "Everything has to be done, that's why this second round is absolutely crucial - and the marching order is simple: unity, and mobilisation."
Polling agencies that have calculated the numbers precinct-by-precinct say the Socialists and allies could win an absolute majority in the 577-seat Assembly in the final round.
It would cap the left's near-universal control of France's political landscape. The Socialists won control of the Senate last year, they or their allies run 21 of mainland France's 22 regional governments and Socialist mayors run many big cities including Paris, Lille and Lyon.
The Socialists were once badly riven by personal infighting and ideological clashes over issues like the ill-fated European Union Constitution referendum in 2005. But over the past year, their political-campaign management has improved, allowing the Socialists to capitalise on sluggish economic growth, high state debt and disillusionment with Mr Sarkozy's brash style to oust conservatives from years in power.
An absolute Socialist majority in the National Assembly, where bills originate and require final passage before becoming law, would give Mr Hollande a free hand to pass, or reject, possible European Union treaties in the future and bypass more EU-skeptic parties of the far left.