Mr Barre, 70, an unaffiliated centrist, said in a radio interview he would take up to three months to decide whether to contest the election, the first round of which will be held on 23 April. Polls show support for him has jumped by about 15 points since the outgoing European Commission President, Jacques Delors, announced last month that he would not join the race to succeed President Francois Mitterrand.
Commentators say Mr Barre, a pro-European economist who was prime minister from 1976 to 1981 after serving on the European Commission, could take votes from the Prime Minister, Edouard Balladur, who is the conservative front-runner, as well as the centre-left. Mr Balladur is expected to announce his candidacy later this month.
Ten cabinet ministers have publicly endorsed Mr Balladur while only three have backed his most serious rival on the right, Jacques Chirac, mayor of Paris.
Europe-1 radio said at least 60 Gaullist parliamentarians would publish a call next week for Mr Balladur to run in preference to Mr Chirac, their party's founder, who has already declared his candidacy but trails third in the polls.
The National Front's Jean-Marie Le Pen has also announced his candidacy, and another right-wing contender, the anti-Maastricht campaigner Philippe de Villiers, is expected to join the race shortly.
In a Europe-1 interview, Mr Barre called for more energetic measures to cut employers' payroll taxes, improve job training and increase labour market flexibility to combat France's 12.6 per cent unemployment rate. He also called for reform of the tax system, and further steps to make the justice system independent of government.
The Left, cast into disarray by Mr Delors' shock withdrawal in December, was further unsettled by Mr Jospin's offer to stand for the Socialist party.
Mr Jospin's long-standing rival, the former prime minister Laurent Fabius, implicitly disavowed his candidacy, saying: "We must choose a person ... capable of uniting all Socialists and the non-socialist Left.Reuse content