Mr Balladur, the Prime Minister, was recently given a taste of what is to come when he was subjected to biting criticism from his two rivals on the right after he bowed to pressure from students and rescinded a plan to reform technical education.
Jacques Chirac said that it showed the limits of Mr Balladur's tactic of "small steps forward and small steps back". The anti-Maastricht campaigner Philippe de Villiers accused him of "prejudicing the authority of the state" by "back-tracking every time a measure provoked street demonstrations".
Mr Balladur's supporters say that it is right for controversial measures to be suspended until after the election.
The race that will be decided in two rounds on 23 April and 7 May is hotting up. Mr Chirac launches his manifesto on Friday at a rally in Paris. The Socialist Party has finally settled on a candidate, Lionel Jospin, and the veteran centre-rightist, Raymond Barre, says that he will announce in the next week or so whether he will stand.
Mr Jospin last night demanded an explanation from Mr Balladur over a "dirty trick" case which he said had "all the ingredients of a considerable affair of state". Speaking on television, Mr Jospin called on Mr Balladur to make a statement, after the Paris court of appeal last week threw out police phone-tapping evidence against sexologist Jean-Pierre Marechal. The phone-tap was apparently aimed at removing Mr Marechal's son-in-law, examining magistrate Eric Halphen, from an investigation into illegal financing of Mr Balladur's RPR party. Mr Jospin called for a parliamentary inquiry into the case.
A host of minor candidates is gathering, among them Mr de Villiers, the Communist leader, Robert Hue, Jean-Marie Le Pen of the National Front and the leader of the Greens, Dominique Voynet.
Although Mr Balladur is still a long way ahead in the opinion polls, with the support of about 28 per cent of electors, recent polls show that his lead over his two main rivals is narrowing.
Mr Chirac and Mr Jospin are running neck-and-neck for second place, with between 17 and 19 per cent of the votes each.
But there is a large number of "don't knows" and if Mr Barre stands, the outcome of the first round of voting could be hard to predict.
One feature of the campaign has been a concentration on personalities to the virtual exclusion of policies. This may be partly because there are two - if Mr Barre stands, three - candidates from the RPR/UDF bloc and until Mr Jospin was chosen, there were two rivals for the Socialist nomination.
Even so, the voters and the media commentators rarely refer to parties and their policies. Instead, they talk of the Balladurists, Chiraquists, Jospinists and even Lepenists. Their rivalry, moreover, has been discussed in terms of personal alliances and foibles and not in terms of what they might do if they won. There is plenty of policy discussion, but only outside the context of the election.
In the academic institutes, in the media and on the streets, people are talking about unemployment, middle-class insecurity, the need to reduce the budget deficit, the cost of the health service, the state of the family (the number of divorces overtook the number of marriages for the first time last year), and, above all, about education.
Little of this has entered the election campaign. Mr Balladur's decision to suspend plans for reorganising technical education was discussed in terms of his tendency to back-track, not on the merits of the proposals.
It is as though the candidates know that whoever wins will need to make unpopular choices - first, to reduce the budget deficit - but no one wants to be first to mention it. There is, certainly, widespread fear that the wave of labour and student unrest will explode into a hot summer after the election, especially if Mr Balladur wins.
But a highly personalised campaign will not necessarily benefit Mr Balladur. The Prime Minister is evasive in television interviews, appears wooden when he encounters ordinary people and, if a recent book and newspaper articles are more than just the orchestrations of a rival, there may be skeletons in the cupboard of his personal life and business dealings.
Mr Chirac is a far better campaigner in the flesh, while Mr Jospin is considered incorruptible. Mr Balladur's trump card is that he looks like a president and already conducts himself like one, with confidence and authority.
As the Prime Minister, he has also constant media exposure in the role of leader, something that his rivals resent.
Mr Jospin's main task, like that of Mr Chirac, is to win through to the second round. Each candidate is now engaged in trying to present himself as the principal rival to Mr Balladur. Because of this, there has been no real left-right debate, and the ideological lines have often seemed blurred.
Before the Socialists had settled on their candidate, it looked as though the political contest would be between the right and the further right. Some regarded this as an accurate reflection of the political climate. Others, however, pointed out that either of the main candidates on the right might well pursue more liberal policies than the present presidential incumbent.
During his 14 years in office, the Socialist President, Franois Mitterrand, has overseen the privatisation of nationalised industry, budget cuts and the strong-franc policy. One observer quipped: "Mitterrand has always been faithful to the ideals of his youth - the extreme right. He broke the Communist Party and rehabilitated Vichy."
One magazine columnist said this weekend that he hoped the entry of Mr Jospin into the race would stop the right from trying to reinvent a policy of the left. But Mr Chirac's problem is still to set enough distance between himself and Mr Balladur. He has tried hard to court different interest-groups - small businessmen, farmers and the rural population - but it is not clear with what success.
Some believe the traditional left-right split in France is growing less important. A recent poll showed that 48 per cent of voters see the main political divide as being between left and right, compared with 55 per cent at the time of the last presidential elections in 1988.
That may reflect no more than nostalgia among the Paris intelligentsia, but a new mood can be detected since the election of Mr Jospin, a mood that warns against writing off the Socialist candidate too soon.