The president's main motive is damage control. He needs to avoid his ruling Gaullist-led coalition losing more seats than it otherwise would have if he had allowed the National Assembly to run its full five-year term until next March. He wants to give himself a working majority in Parliament for the rest of his time in the Elysee, until 2002.
This would enable him to steer France into European economic and monetary union, free of short-term electoral constraints.
However, a complete upset -- for France and to some extent for Europe -- is possible. French voters could decide to take out their anger about record unemployment on the government of Alain Juppe, the prime minister, and vote it out of office.
The shock would be acute because to be in a position to form a majority, the Socialists would have to ally themselves with the Communists, who are viscerally opposed to the single European currency. The narrower a Socialist margin of victory, the more the party will be beholden to the Communists.
It is highly unusual for any leader to call a snap election, knowing he is going to lose a large number of his troops. But President Chirac does start with an enormous number of them.
In 1993, the Gaullist RPR and its junior centre-right coalition partner, the UDF, won virtually the biggest conservative landslide since the Bourbons returned after Napoleon. Despite some minor by-election losses since, they still hold 464 out of the National Assembly's 577 seats.
The RPR-UDF leaders knew they would lose about 100 seats, as the pendulum of French politics swung back a bit to the centre. They have convinced Chirac that the longer he waits the bigger the losses will be.
There is a long pre-history to this dissolution. Juppe himself has long regretted Chirac's 1995 campaign promise not to dissolve the national Assembly if he won the presidency.
President Chirac's promise not to do the same was rooted in his internecine struggle with Edouard Balladur to be the Gaullists candidate.
Balladur had suggested that he would follow victory with a dissolution. So Chirac -- desperate at that stage to curry favour with "the class of 1993" in his own party, made the counter-promise that they could hang on to their seats.
The upshot was that Juppe never quite managed to put his own stamp on Parliament, though in autumn 1995 he did persuade Chirac, under the pressure of a run on the franc, to let him give priority to deficit reduction over job-creation.
The past two years have been a learning exercise for both president and prime minister who by the standards of the Fifth Republic have formed an usually close and loyal team.
Juppe has accepted that the public sector strikes, which brought the country to a near standstill in late 1995, showed the political wisdom of Chirac's gradualist approach to slimming down the bloated French state.
For his part, Chirac has stood by Juppe, even when the latter last year broke all records for prime ministerial unpopularity.
The president has shown no appetite for switching premiers. Of the two obvious Gaullist successors, Phillippe Seguin, the National Assembly president, remains too Euro-sceptical, while Jacques Toubon, the justice minister and nominal number two to Juppe, is seen as lacking the requisite stature.
So Chirac gave in to Juppe's pressure for a new majority. Two factors clinched the argument for dissolution. The first relates to the politics of austerity. The government is in the throes of preparing a 1998 budget, to be announced in September.
The government may have to screw the lid down even tighter because next year it will not be able to repeat the windfall pension-related payment from France Telecom that eased the fiscal balance this year.
The second factor has only become obvious to Chirac and his psephologists in the past few weeks: a certain weakness on the left and a growing menace from the far right.
Jospin is having obvious difficulty in gearing up his Socialist challenge. This relates partly to himself. His image is bland, schoolmasterly. To make matters worse, he lacks a seat in Parliament.
By contrast, the rise of Jean-Marie Le Pen's far-right National Front (NF) has created alarm. Its rise may be more apparent than real. It has just scored another municipal victory in the south and its congress in Strasbourg last month generated huge publicity. But the Front's general standing has not risen above about 15 per cent.
So how will it all play out, against a background of rising economic growth and stubbornly high unemployment?
Much depends on whether the French electorate regards the election as sufficiently important to have their month of May taken up by it. The French are not used to snap elections, and the constitutional theory on them such as it is , is that they should be justified by some kind of crisis.
So what probably lies in store for the French people if they reelect the centre-right is continued spending restraint, incremental reductions in the civil service and another attempt at public pension reform, less drastic than the failed reform of 1995.
On a wider front, Chirac sought to dress up the election as essential to give the French people a voice in reform of EU institutions, enlargement of the EU and reform of Nato.
Yet none of these issues appear to interest the French public in the slightest. Only on the issue of "the passage to the euro" did the president strike a seriously sensitive political chord.
The euro will be the wild card of this election. It divides both left and right. The Socialist party is torn by how far to compromise its support for the euro in a deal with the Communists. Senior Gaullist Eurosceptics like Charles Pasqua will want to turn next month's election as far as possible into a referendum on the single currency. Even by holding the election nearly a year ahead of the EU's planned decision on which countries will first form EMU, Chirac was never going to be able to neutralise the issue. For the struggle to qualify for the euro is here and now. David Buchan
