Francois Hollande is the man in charge after his Socialist Party swept France's parliamentary election.
Voters welcomed the French president's vision of injecting government money into Europe's economies in hopes of helping the joint euro currency stave off disaster.
Socialists now have an unprecedented lock on politics in France, and plan to use it to raise taxes on big banks and oil companies, levy a 75% tax on incomes higher than one million euro a year, and hire 60,000 teachers.
Mr Hollande's strong domestic mandate will let him push back in global economic talks against the budget cuts being demanded by Germany, which Greece and other indebted countries say are driving them deeper into the financial abyss by suffocating growth.
France's election also gave the far right National Front a toehold in parliament, a small but symbolic victory for a party that wants to stop immigration, dump the euro currency and decries the so-called "Islamisation" of France.
The conservative UMP party of former president Nicolas Sarkozy, which dominated the outgoing parliament, suffered the biggest losses.
The balloting to elect 577 politicians for France's lower - and more powerful - house of parliament came on the same day that conservatives won a parliamentary election in Greece.
With final results still coming in, pollsters estimated France's Socialists and their closest allies will hold between 313 and 315 seats, well over the 289 needed for a majority and exempting them from horse-trading with far-leftists who oppose some of Mr Hollande's pro-European policies.
"This score exemplifies strong confidence in the president," said Finance Minister Pierre Moscovici, who won his own race for an Assembly seat. This gives a spinal column to the government and strengthens it ... our commitments will be honoured. We will not do any austerity."
Mr Sarkozy's UMP party went from 304 seats in the old Assembly to an estimated 214 in the new one, after Mr Sarkozy himself lost his re-election bid to Mr Hollande just six weeks ago.