François Hollande's presidential triumph tore up the French electoral map and promises a relatively easy victory for the left in parliamentary elections next month.
Mr Hollande topped the poll in 333 of 577 parliamentary constituencies, including many which have traditionally leaned to the right. A three-way split in the opposition between centre, right and far-right suggests his Socialists and their Green and hard-left allies will win by a wide margin when voters go to the polls once again in parliamentary elections on 10 and 17 June.
In the outgoing National Assembly, Nicolas Sarkozy's centre-right party, the UMP, and its allies held 329 out of the 577 seats. The new electoral topography suggests the left will win a majority at least as large on 17 June. In any case, for the past half century French voters have always given a healthy parliamentary majority to a newly elected president.
The regional and sociological breakdown of last Sunday's vote points to a France deeply divided between east and west, young and old, rich and poor. Looked at another way, it gives Mr Hollande an overwhelming majority among all age categories except the over-65s and all social categories except farmers, the retired and the wealthy.
An opinion poll by Viavoice for the newspaper Libération suggests Mr Sarkozy owed the closeness of his defeat almost entirely to the "wrinkly" vote. Overall, Mr Hollande won by 51.7 per cent to 48.3 per cent. Among the over 65s, Mr Sarkozy won by a landslide – 60 per cent to 40 per cent. Among, 18- to 24-year-olds, Mr Hollande won by the same landslide score. In all other age categories, the Socialist President-elect topped the poll comfortably with between 53 and 56 per cent.
There were also significant sociological shifts. The blue-collar and salaried workers who have voted for centre-right candidates in recent elections came back to the left in huge numbers. In 2007, Mr Sarkozy had a majority among ouvriers or blue-collar workers. On Sunday, Mr Hollande took 68 per cent of the vote in this category (including many who voted for the far right in the first round).
Geographically, Mr Hollande swept the board in Brittany, the north, the centre and the south-west. He won in every large city.
Mr Sarkozy polled strongly in the east, especially Alsace and Lorraine and the Rhone valley and Mediterranean coast from Marseilles to the Italian frontier. He also did well in a band of rural or semi-suburban départements from Normandy to Champagne.
The result is that the electoral geography looks promising for the Socialists in the parliamentary polls. Any candidate who scores 12.5 per cent of the registered vote in round one can go forward to a "British- style" first-past-the-post election in round two.
The Socialists have agreements with the Greens, Communists and others that the weaker of two left-wing qualifiers will stand down. To the fury of some on the right, no such deals are allowed by the centre-right UMP with the newly powerful, far-right National Front. As a result, the left is likely to top the poll in scores of extra seats.