Mr Sarkozy meanwhile has been campaigning with labour minister Jean-Louis Borloo and lightly mocked Ms Royal's televised debate at a hotel in Paris.
He was quoted by the Reuters news agency as saying: "I prefer being on the ground with Jean-Louis Borloo.
"It's symbolic. There's two in a big Parisian hotel and us two on the ground."
Ms Royal used the debate to highlight issues which she feels she shares with Mr Bayrou, although the former candidate also noted the differences that still remain between the two.
This year's election offers a clear choice between the right and the left for the French people and Ms Royal hopes those who are worried about Mr Sarkozy's hardline image may move towards her candidacy.
A recent Ipsos poll showed that Ms Royal was trailing Mr Sarkozy with a 47.5 per cent share of the vote compared to 52.5 for the former interior minister.
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