Around the time of the attack, Assad's regime feared a possible opposition strike on Damascus: "Our evaluation is that the regime was looking to loosen the vice and secure the strategic sites for the control of the capital," the report said.
The synopsis also said French intelligence services had collected urine, blood, soil and munitions samples from two attacks in April — in Saraqeb and Jobar — that confirmed the use of sarin gas.
France is "determined to take action against the use of chemical weapons by the regime of Bashar Assad, and to dissuade it from doing so again," Prime Minister Jean-Marc Ayrault said after hosting lawmakers to discuss the intelligence on Syria. "This act cannot go without a response."
France won't act alone and Hollande was "continuing his work of persuasion to bring together a coalition," Ayrault said. French parliament will debate the Syria issue Wednesday, but no vote is scheduled. The French constitution doesn't require such a vote for Hollande, though he could decide to call for one.
Russia, which along with Iran has been a staunch supporter of Assad through the conflict, brushed aside Western evidence of an alleged Syrian regime role.
"What our American, British and French partners showed us in the past and have showed just recently is absolutely unconvincing," Russian Foreign Minister Sergey Lavrov said Monday before the French report was released. "And when you ask for more detailed proof they say all of this is classified, so we cannot show this to you."
"There was nothing specific there, no geographic coordinates, no names, no proof that the tests were carried out by the professionals," he said, without identifying which tests.
Russian President Vladimir Putin proposed to send a delegation of Russian lawmakers to the U.S. to discuss the situation in Syria with members of Congress. Two top Russian legislators suggested that to Putin, pointing to polls that have shown little support among Americans for armed intervention in Syria.