Voters in 497 of France's 577 National Assembly constituencies will choose deputies for the next five-year legislature, with as many as 80 per cent of the seats going to the conservative alliance of the Gaullist RPR and the centre-right Union for French Democracy (UDF) and dealing a humiliating blow to President Francois Mitterrand's Socialist Party. The right took the other 80 seats with victories in the first round of voting last Sunday.
Constitutionally, the arrival of a conservative government does not affect the ability of Mr Mitterrand, 76, to serve out the final two years of his mandate, as he did during the first left-right cohabitation from 1986 to 1988. But politically, his position is extremely delicate.
As the Socialists, despite calls to turn out and limit the right's victory, showed little fighting spirit last week, the conservatives were at first modest about their nearly 40 per cent vote, more than double the Socialist total, apparently to create an air of serenity for the second round.
It was Jacques Chirac, 60, the Gaullist leader and likely presidential candidate, who broke this spell by saying that the President should step down.
This brought an angry reaction from the Elysee Palace, where officials said the President might not, after all, choose a Gaullist prime minister if the RPR, likely to be the bigger of the two conservative groups in parliament, were to demand his departure.
This upset what had hitherto become almost a consensus, that Edouard Balladur, the 1986-88 finance minister, would lead the government for the Gaullists, and brought a climbdown from Mr Chirac, who said: 'No one disputes Mr Mitterrand's constitutional right to finish his mandate.'
Whatever papering over the cracks there may have been to calm the atmosphere until polling stations close this evening, there is no doubt that calls for Mr Mitterrand to go are likely to rise in a crescendo. With a traditional pre-eminence over defence and foreign affairs, conservatives fear the President will try to exercise an influence out of proportion to his political support.
Philippe de Villiers of the UDF, a leader of the anti-Maastricht campaign last year, has called on conservative deputies to meet from tomorrow to discuss the President's position. While this call is likely to be ignored as the country awaits its new government, such appeals are likely to increase in the days to come.
A crucial day may be Friday, when the new National Assembly session opens. With about 100 new members savouring the excitement of victory, it is almost inconceivable there will be no attempts to table motions questioning the President's position.
With the Socialists terribly weakened in parliament, this will leave Mr Mitterrand to fight his battles alone.
The final week of campaigning has produced little to indicate any change in voter sentiment. With the Socialists rocked by recession and unemployment and their image tarnished by scandals, their appeals to limit the right's victory are unlikely to have much effect.
Several Socialist stars are expected to be defeated today, most notably Michel Rocard, the ex-prime minister, and Roland Dumas, the Foreign Minister.