The far-right National Front party has won its first ever seats in France's Senate as president Francois Hollande's Socialist party lost its majority in the upper house of parliament.
Preliminary results of Sunday's ballot reflect the unpopularity of the president, who has failed to revive the country's ailing economy, and the mirrors the continued rise of the anti-immigration, anti-Euro National Front.
The party, led by Marine Le Pen, took two seats in the Senate, following on from the party's surprise victory in European parliamentary elections in May and its strong showing in municipal elections in March.
"These results are beyond what we hoped for," said Le Pen. "Each day that passes, our ideas are increasingly being adopted by the French people. We have great potential."
"There is only one door left for us to push and it is that of the Elysee," said newly-elected National Front senator Stephane Ravier, referring to the French presidency.
A Senate spokesman said a final count would await tallies from all of France's overseas holdings, which is not likely until Monday, but it was already clear that the centre-right UMP were back in control of the 348-seat chamber.
The Socialists still control the lower house, which has the final say in drafting laws in France.
The French electoral system elects half of the Senate every three years, with senators holding six year terms. Only some 158,000 people, the vast majority local councillors, are able to vote in these polls.
Early results showed that the main opposition party, the UMP, and the centre-right UDI party took at least 20 seats from the left, which had a Senate majority of just six heading into the election.
"There is a complete rejection of Socialist policies," UMP senator Roger Karoutchi told BFM TV.
This unpopularity may have encouraged the comeback of former Nicolas Sarkozy, who announced last week his intentions to seek the presidency of UMP in a move that could be the first towards running for country's top post by 2017.
Hollande's popularity fell to a record low this month, with only 13 percent of those surveyed saying they were satisfied with the performance of president, who has struggled to revive the stagnant economy.
The National Front has successfully capitalised on growing discontent over unemployment and resentment over immigration, and hopes to score an upset in the 2017 presidential election.