By Paul Taylor and Daniel Flynn
PARIS (Reuters) - France's main presidential candidates have drawn clear battle lines over austerity, Europe and Germany as opinion polls show the gap between them narrowing five weeks before the first round of voting.
Socialist challenger Francois Hollande, whose wide poll lead over conservative President Nicolas Sarkozy has shrunk in the last week, raised the stakes in a television appearance on Thursday after winning public support from German and Spanish opposition leaders for his stance.
Hollande said that if elected he would not submit a German-inspired European treaty enforcing strict budget discipline for ratification unless it were "completed" by a growth component.
"We have to put growth back into Europe and we should adapt our deficit-reduction targets accordingly," the Socialist told France-2 television.
Sarkozy has said France cannot reopen a treaty that has been signed by 25 countries, but Hollande said he intended to "change the direction of the continent" and renegotiate the fiscal pact.
German Social Democratic party leader Sigmar Gabriel and Spanish Socialist chief Alfredo Perez Rubalcaba endorsed Hollande's call to add pro-growth amendments to the treaty.
Sarkozy's supporters accused Hollande of pandering to voters by abandoning France's pledge to cut its budget deficit.
Invoking the famous "J'accuse" cry of 19th century author Emile Zola, Prime Minister Francois Fillon said in the daily Le Figaro: "I accuse the Socialist candidate of having deliberately chosen to give up on lowering the deficit. I accuse him of not wanting to lower state spending for fear of upsetting people.
"I accuse him of having given up respecting France's European commitments," Fillon said, warning that any backsliding could reignite the euro zone's debt crisis.
Hollande insists he will stick to the current government's promises to reduce the deficit to 3 percent of gross domestic product in 2013 but will take a year longer than Sarkozy has pledged to achieve a balanced budget, aiming for 2017.
The Institut Montaigne public policy think-tank said in an audit that Hollande had overestimated future revenues by 15 percent. Sarkozy has not yet published a full program so his figures cannot be audited, it said.
KNOCK OUT RADICALS
Because of a two-round voting system, in which the top two candidates meet in a runoff on May 6, both Sarkozy and Hollande first have to knock more radical contestants on the right and left out of the race.
Sarkozy has sought to win back voters from far-right anti-immigration candidate Marine Le Pen by threatening to pull out of Europe's open-border zone unless external border controls are toughened, and to impose unilateral trade barriers unless the EU imposes tougher reciprocity rules in public procurement.
Le Pen is running third with about 16 percent of the vote.
But by shifting to the right, the president risks alienating centrist voters backing centrist candidate Francois Bayrou, credited with about 12 percent in the polls.
Sarkozy's mercurial temper got the better of him when he called a reporter a "couillon" (prick) for asking him about the use of tear gas against protesting steelworkers near his campaign headquarters on Thursday. He later apologized.
Hollande, for his part, has tried to stem rising support for hard left candidate Jean-Luc Melenchon - hovering around 10 percent - by proposing a 75 percent top income tax rate on earnings over 1 million euros a year, and by demanding a renegotiation of the fiscal pact.
"Germany should not decide the direction of Europe alone," Hollande said in his television interview, playing on concerns that German Chancellor Angela Merkel is imposing austerity across the continent at the expense of growth and jobs.
With candidates required to submit 500 nominating signatures from elected officials by a 6 p.m. (1700 GMT) deadline on Friday, Sarkozy received a small boost when bitter rival, former Prime Minister Dominique de Villepin said he would fall short.
Villepin, a conservative Gaullist close to ex-President Jacques Chirac, who had barely 1 percent support in opinion polls, refused to endorse any other contender, but his exit means less division on the mainstream right.
Sarkozy overtook Hollande for the first time this week in voting intentions for the April 22 first round in one opinion poll and drew level in another.
However, several other surveys gave the Socialist a first-round lead and all polls still show him beating the incumbent by a margin of at least eight points in the runoff.
Villepin's fall means there are likely to be 10 candidates, including two Trotskyists, a Green, an anti-euro sovereignist, and maverick Jacques Cheminade, an associate of U.S. conspiracy theorist Lyndon LaRouche.
The official campaign begins next Tuesday, with candidates' television time rationed to strict equality.
(Additional reporting by Vicky Buffery, Emmanuel Jarry and Elizabeth Pineau; Writing by Paul Taylor; editing by Janet McBride)