By James Coomarasamy BBC Paris correspondent

The French Socialist Party has announced it has reached an electoral agreement with other parties on the left to field single candidates in some constituencies in next month's parliamentary elections.

First round voting intentions

41% to centre-right 39% to left 12% to far-right

Source: Ipsos poll

This agreement is an important one for the party, after its disastrous showing in the presidential election, when its candidate, Lionel Jospin, failed even to make it to the second round.

Second round voting intentions

53% to centre-right 47% to left

Source: Ipsos poll

If the Socialists do well enough in the parliamentary election to form the next government, they will ensure they do not spend the next five years in the political wilderness.

They will also oblige President Jacques Chirac to co-habit once again with an administration from the other side of the political spectrum.

Rallying supporters

The Socialists have struck a deal with their former partners in government - the Greens, the radical left and the Communists. In at least 34 constituencies only one candidate will stand, and in more than 130 others, "bilateral" deals have been struck between some of the parties.

Jospin's defeat to Le Pen shocked France

It is less than a half of the total number, but a start all the same.

The fragmented left-wing vote was one of the factors which let the far-right leader Jean Marie Le Pen beat Mr Jospin in the presidential race.

Under their new leader, Francois Hollande, the Socialists know that their success depends on the party's ability to rally their supporters to come out and vote as they did in the second round of the presidential election.

On that occasion millions of left-wingers voted for the Gaullist candidate Jacques Chirac in order to prevent Mr Le Pen from becoming head of state.