French President Nicolas Sarkozy said on Monday he would stick to a target of 115 billion euros in budget savings up to 2016 when he presents his re-election manifesto in the days ahead.

Sarkozy is battling to overturn deep disillusionment with his presidency, including among many who voted for him in 2007, that is due in part to three years of economic gloom and in part to a widespread dislike of his personal style.

The conservative leader, who is lagging Socialist challenger Francois Hollande in opinion polls, told reporters in Nancy he will outline his election programme on Thursday after his return from a trip to the French Indian Ocean island of Reunion just two weeks from the first-round vote on April 22.

His goal was 75 billion euros ($100 billion) in spending cuts and 40 billion in new revenues over the next five years, he told the regional dailies Est Republicain, Republicain Lorrain and Vosges Matin.

I think that right until the end of the campaign, I'll be presenting new ideas, Sarkozy said after visiting a factory in eastern France. I want to be free to announce ideas, to make proposals to the French for the next five years that take the campaign forward. Otherwise why bother campaigning?

Sarkozy already has parliamentary approval for measures that would bring in 32 billion euros of additional income and he said he intended to secure the remaining 8 billion through new taxes on big companies and by making tax exiles pay contributions.

Sarkozy had opted to delay his re-election programme until the last moment and instead unveil proposals one by one for maximum impact and to contrast with Hollande, who detailed a weighty programme in January based around raising taxes on the rich to fund investment in education and jobs.

Seeking to capitalise on his verve as a campaigner, he has made headlines with proposals to hold policy referendums, cap immigration, make the long-term unemployed undergo training to keep their benefits and to push for a Buy European Act.

The Socialists say the blow-by-blow campaign strategy makes Sarkozy look ill-prepared. Hollande's campaign chief Pierre Moscovici told LCI television it was irresponsible to give budget figures without explaining where they came from.

It shows a lack of democratic transparency, he said.

Aides say Sarkozy's campaign chief Emmanuelle Mignon is preparing a 16-page manifesto.

This will be our reference document but there could be more proposals, said lawmaker Damien Meslot, a member of Sarkozy's campaign team. In this campaign, our weapon is surprise.

FOCUS BACK ON ECONOMY

The election race is expected to pick up pace this week after being thrown off course by a spate of shootings by an al Qaeda-inspired gunman, whose killing of seven people prompted candidates to suspend their campaigning for several days.

The focus is also returning to the economy, which is at the top of voters' concerns as purchasing power has been battered by first the global economic crisis then a euro zone debt crisis that has left Europe's recovery lagging North America's.

Unemployment, which Sarkozy vowed in 2007 to combat, is now higher than before the 2008 crisis, even if France has resisted dipping into a recession again in recent months.

This month's shootings saw Sarkozy, a law-and-order leader who thrives in a crisis, inch up slightly in opinion polls although Hollande is still in a clear lead for a May 6 runoff.

Most voter surveys now put Sarkozy 1-2 points ahead of Hollande for the April 22 first round, while Hollande's lead for round two has narrowed to 8 points from around 12.

Sarkozy was closing the gap even before the shooting attacks in the southern city of Toulouse as he shifted right with a pledge to halve the number of legal immigrants entering France each year and step up deportations of those arriving illegally.

As the campaign returns to issues like employment and public finances, Sarkozy may draw some benefit from data on Friday showing France's 2011 budget shortfall was 5.2 percent of gross domestic product versus an initial target of 5.7 percent.

The figures prompted the government to trim its 2012 deficit target to 4.4 percent of GDP from 4.5 percent previously.

Sarkozy has already said he hopes to bring in 2-3 billion euros extra per year by imposing a minimum tax on around 100 international companies headquartered in France who have in the past used fiscal loopholes to lower their French taxes.

He also hopes to net some 500 million euros a year by making tax exiles pay France the difference between the taxes they pay abroad and what they would have paid if still domiciled here.

A jump in consumer spending, a key growth motor for the No. 2 euro zone economy, in February was good news for Sarkozy.

But Monday brought more gloom with manufacturing sector data that showed factory activity suffered its biggest one-month decline in 33 months in March, throwing into question Sarkozy's claim that the economy has turned a corner.

($1 = 0.7509 euros)

(Additional reporting by Catherine Bremer; Editing by Karolina Tagaris)