President Nicolas Sarkozy threatened to pull France from Europe's passport-free zone unless the European Union tightens its borders against illegal immigration.
"At a time of economic crisis, if Europe doesn't pick those who can enter its borders, it won't be able to finance its welfare state any longer," center-right Sarkozy, facing a tough re-election fight against a Socialist, told a campaign rally of 60,000 near Paris-Charles de Gaulle Airport.
He threatened to pull France out of the so-called Schengen treaties, which permit free travel within most EU borders, if the rules are not changed within a year to curb illegal immigration.
"We can't leave the management of migration flows to technocrats and tribunals," he said Sunday in what analysts said was a bid to capture the far-right National Front nationalist political party, whose big issues are economic protectionism, a zero tolerance on law-and-order issues and a strong opposition to immigration.
"We must undertake a reform of Schengen as structural as the reform we have just put in place for the euro," he told the rally.
Sarkozy's speech came five days after he declared there were "too many foreigners in France" and promised to cut the immigrant influx in half -- comments that sparked outrage among many French on the left and those of foreign descent.
Sarkozy told the crowd Sunday he would, if re-elected, demand EU partners pass a "Buy European Act" similar to the 1933 "Buy American Act," which requires Washington and other purchasers using federal funds to prefer U.S.-made products.
If the EU fails to implement the act within a year, he would impose a unilateral "Buy French" law, he said.
"I want a political Europe that protects its citizens," Sarkozy said.
The loudest cheer came when he said he opposed separate hours for men and women in swimming pools and Islamic halal food -- food deemed permissible under Islamic law -- in school-lunch programs, the British newspaper The Daily Telegraph reported.
Sarkozy, of the center-right Union for a Popular Movement, trails Socialist Party rival Francois Hollande in most opinion polls less than six weeks from the first round of the presidential election April 22.
An OpinionWay-Fiducial poll conducted March 5-7 and released Thursday indicated 29 percent of potential voters would chose Hollande if the first round were held now, while 26 percent would pick Sarkozy.
Centrist Democratic Movement candidate Francois Bayrou is polling third for round one with 15 percent, tied with anti-euro candidate Marine Le Pen.
The poll has a margin of error of 2 percentage points to 3 percentage points.
The second-round runoff takes place May 6.
"Help me prove [the polls] wrong," Sarkozy implored supporters.
The 1985 Schengen Agreement and a 1990 follow-up treaty abolished internal border controls within the EU and some non-EU countries, including Switzerland and Iceland, with two EU member states -- Ireland and Britain -- opting out.
The treaties make the 26-country Schengen area very much like a 400-million person, 1.7 million-square-mile state for international travel, with external border controls for people traveling in and out of the area, but with no internal border controls.