President Nicolas Sarkozy's government has lost its majority in the French Senate.
The Socialist Party and its Communist and Green allies have won enough seats to gain control of the upper house.
Right-wing parties have controlled the Senate since the Fifth Republic was founded in 1958.
The BBC reports that early results from elections on Sunday showed left-wing candidates took at least 23 seats from the governing party, giving them an absolute majority.
Of the 170 seats in the election, Mr Sarkozy's UMP party had 147 seats out of a total 343 to the Socialist Party's 115 before the vote.
The number of seats in the upper house is being increased to 348 to reflect an increase in population.
A presidential election is due in April.
