Sarkozy, who has announced plans to punish those viewing Islamist websites and going abroad for indoctrination, said he would block the entry of some imams invited to a congress organised by the Union of French Islamic Organisations.
The union, one of three Muslim federations in France, is regarded as close to Egypt’s Islamist Muslim Brotherhood.
“I have clearly indicated that there are certain people who have been invited to this congress who are not welcome on French soil,” Sarkozy said.
He cited Sheikh Yusuf al-Qaradawi, an Egyptian cleric based in Qatar who is one of the most prominent Sunni Muslim clerics in the world and a household name in the Middle East due to his regular appearances on Al Jazeera.
A former member of the Muslim Brotherhood, Qaradawi is independent of the group but remains close to it. Sarkozy said the situation was complicated because the imam holds a diplomatic passport and does not require a visa to enter France.
“I indicated to the Emir of Qatar himself that this person was not welcome on the territory of the French republic,” Sarkozy said. “He will not come.”
Qaradawi was denied a visa to visit Britain in 2008 on grounds of seeking to “justify acts of terrorist violence or disburse views that could foster inter-community violence”, a Home Office spokeswoman said at the time.
Sarkozy, campaigning for re-election, has rebutted criticism by opposition politicians that the security services blundered in allowing 23-year-old Mohammed Merah, a petty criminal known to have visited Afghanistan twice, shoot dead seven people in a 10-day rampage in south-west France.
The killing spree by Merah, who shot dead three Jewish children and four adults before he was killed by police commandos at the end of a 30-hour siege on Thursday, has pushed security to the top of the political agenda.