"Today he is a criminal. He is the principal person responsible for the orders to kill and arrest tens of thousands of Syrians," Ghalioun, who moved to Paris in 1978 and teaches sociology in a Paris university, added. "How can he escape punishment?"
Syrian dissidents established the "national council" in Istanbul on August 23 to coordinate the campaign to topple Assad and formally formed a common front uniting all groups that oppose his regime last week.
On Monday the European Union welcomed its formation and urged the world to do the same, as it readied new sanctions against Assad's regime.
"No Syrian ... would accept to talk with Assad or see him as the representative of the Syrian people ... There will be no compromise with this dictatorial regime," added Ghalioun.
"He must resign and get out of Syrians' life because he has become a symbol of the destruction of the state."
"Enough blood, enough mistakes, enough crime, spare your people," he said, addressing the embattled president.
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