PARIS -?French President Nicolas Sarkozy on Sunday said in a reelection campaign speech that the border-free Schengen agreement should be rethought and re-founded.

Sarkozy made the remarks while addressing some 60,000 supporters in Villepinhte in the suburbs of Paris, just a few weeks ahead of the first round of the French presidential election vote scheduled for April 22.

"The Schengen Agreement can no longer respond to the seriousness of the situation. They must be revised. There is a need to implement a structural reform that we have implemented for the euro," the conservative UMP candidate said.

"We can not leave the management of migration flows only in the hands of the technocrats and the courts ... We need a government policy of Schengen as there is now a government of the euro area," the incumbent president added.

Sarkozy, who is currently lagging behind Socialist Francois Hollande in opinion polls, threatened to suspend France's participation in the Schengen agreement "if there was no serious progress in this direction within 12 months ... (and) until negotiations have been completed."

The Schengen Agreement signed on June 14, 1985, near the town of Schengen in Luxembourg allows migrants to travel across Europe's border-free Schengen zone comprised of the territories of twenty-five European countries that approved the agreement.

In April 2011, when thousands of North African immigrants poured in Europe via Italy after unrests in Libya, Sarkozy and Italian authorities expressed willingness to adjust the Schengen agreement and better regulate illegal immigrants.