De Villepin’s candidacy regarded as one in eye for his bitter rival Sarkozy

The move is likely to complicate life for both the Socialist candidate, Francois Hollande, and president Nicolas Sarkozy, who runs the UMP party that Mr Villepin served under.

By positioning himself as a centrist, Mr de Villepin could take votes from both the other candidates.

But the move was primarily seen in France as a finger in the eye of Mr Sarkozy since the two men –despite inhabiting the same conservative side of the political spectrum – are bitter rivals.

Mr de Villepin was acquitted in September of charges he took part in a smear campaign against Mr Sarkozy. On Sunday, he criticised Mr Sarkozy for not protecting France’s interests at a recent EU summit and imposing several rounds of budget cuts.

With growth slowing and difficult budget cuts likely ahead, both Mr Hollande and Mr Sarkozy have tried to paint themselves as beyond partisanship – possibly because they fear both established parties will be blamed for country’s high debt levels and poor economy.

Mr Sarkozy has not yet officially declared his candidacy.