President Nicolas Sarkozy said on Monday that influential Qatar-based Sunni Muslim cleric Yusuf al-Qaradawi was not welcome in France.
Egyptian-born Qaradawi, 86, has been invited to visit next month by the Union of Islamic Organisations in France (UOIF).
"I told the emir of Qatar himself that this gentleman was not welcome in the territory of the French Republic," Sarkozy told France Info radio.
Qaradawi, who hosts a popular show on Al-Jazeera satellite television, backed Arab Spring uprisings in Tunisia, Egypt and Libya, and has launched a fund-raising effort for the Syrian opposition.
He had been due to attend the UOIF congress at Le Bourget near Paris on 6 April alongside renowned Egyptian preacher Mahmoud al-Masri.
"I said that a certain number of people, who have been invited to this congress and who maintain or who would like to take positions that are incompatible with the republican ideal, would not be welcome," Sarkozy said.
Qaradawi, an internationally renowned Islamic scholar, is known to be the spiritual leader of Egypt's Muslim Brotherhood. He lives in Qatar since being exiled in the 1960s by then president Gamal Abdel Nasser.
Qaradawi has been also banned from entering the United States since 1999.