Nicolas Sarkozy has stepped up his appeal to France's far-right by lauding national identity, borders and French Christian heritage at a vast open-air rally in the shadow of the Eiffel tower.

But the French president was dealt a serious blow by Front National leader, Marine Le Pen, who told her supporters she would not vote for him.

Tens of thousands of Sarkozy's flag-waving supporters, many of them party activists bussed in from the provinces by his rightwing UMP party, turned out at Paris's Trocadero in front of an imposing backdrop of the Eiffel tower.