New French president Francois Hollande's Socialist Party has won an absolute majority in parliament.
Second and final rounds of elections have given the party far more than the 289 seats needed to control the National Assembly.
Party leader, Martine Aubry thanked French voters for putting their trust in the Socialists.
Mr Hollande now has the convincing majority he needs to push through his tax-and-spend agenda to battle the eurozone debt crisis.
The Socialists' bloc obtained 314 seats - an absolute majority in the 577-seat National Assembly - and so will not need to rely on the Greens or the far left.
Earlier estimates showed he right-wing UMP party of ex-president Nicolas Sarkozy and its allies took between 212 and 234 seats, the Greens took 18 to 24, and the Communist-backed Left Front took nine to 11, according to estimates from polling firms Sofres and CSA.
The far-right National Front of Marine Le Pen took one to four seats and the centrist MoDem one or two seats.
Mr Hollande defeated Nicolas Sarkozy in presidential elections in May and then urged voters to give him the majority he needs to steer France through the euro zone crisis, rising unemployment and a faltering economy.