The voting for the lower house of parliament begins with a first round Sunday, followed by runoffs a week later that, along with crucial elections in Greece the same day, will have repercussions for Europe's future.
Here is a look at what is at stake in France's elections and how they work.
Hollande, a Socialist, won the presidency last month and unseated Nicolas Sarkozy, whose cost-cutting measures and abrasive style alienated many French voters. But the parliament is dominated by Sarkozy's conservative UMP party.
The left is on the rebound and polls suggest the Socialists and their allies do well in Sunday's first round voting—but it's unclear whether they will get the solid majority Hollande needs to fulfill the promises he made to disgruntled voters during his campaign.
He wants to raise taxes on the rich, hire more teachers and lower the retirement age for some workers. He wants efforts to end Europe's debt crisis to focus more on growth and less on the budget-tightening Germany and France's conservatives favor. But Hollande has also pledged to reduce France's big deficit and cut some spending.
The new lower house serves for the next five years—coinciding with Hollande's five-year term.
In a peculiar French twist, Hollande could face something called "cohabitation": If the conservatives win control of the parliament, the prime minister's job would most likely go to a conservative, too. That would leave the Socialist Hollande stuck for his entire term with a prime minister and government from the other side of the political spectrum.
LE PEN'S CHANCE
Marine Le Pen's anti-immigration National Front, buoyed by her strong third-place showing in the spring presidential race, is looking to win a voice in parliament for the first time since the 1980s.
Her aims of undoing the euro currency, shrinking immigration, protecting "Frenchness" and fighting what she calls Islamization have won her fans among French voters who fear globalization, and among extreme right movements around Europe.
The only time the National Front was a force in the parliament was 1986-1988, when France briefly allowed proportional representation in the legislature. They had 35 deputies, who lost their seats after the rules reverted to the current system, which favors big parties and makes it harder for extreme parties to secure seats.
If the National Front gets multiple seats this time despite the current rules, that will be a big victory for Le Pen and her effort to de-stigmatize the party. Its founder, Marine's father Jean-Marie Le Pen, has been convicted of racism and anti-Semitism.
HOW IT WORKS
Candidates are running for all 577 seats in the Assemblee Nationale representing mainland France and its overseas territories, from French Polynesia in the South Pacific to Guadeloupe in the Caribbean. The Socialists and their allies are hoping to get at least 289 seats for a majority.
Candidates who win more than 50 percent in Sunday's first round win the seat outright. Many races go to a second round, involving any candidate who garners more than 12.5 percent in the first round.
Several second-round races may end up as so called triangular competitions, with one candidate from the left, one from the right, and one from the far right National Front who can play a spoiler or kingmaker.
After a boisterous, high-intensity presidential race that culminated in Hollande's election on May 6, French voters may be feeling some election fatigue. The legislative race hasn't garnered nearly the headlines or drama of the presidential race, and many polls suggest turnout could be around 40 percent—far less than in Hollande's showdown with Sarkozy.