Paris — The French government sought to bolster the case for military action against Syria on Monday, releasing a declassified summary of French intelligence that ties President Bashar al-Assad’s government to the apparent use of chemical weapons outside Damascus last month.

The report comes as the French public’s apprehension about intervening in Syria is mounting. President Obama’s announcement that he would seek Congressional approval for American military strikes, paired with the British Parliament’s vote against taking part, has left France somewhat isolated on the issue internationally. There are rising calls for a parliamentary vote in France, too, though the French president, François Hollande, has no constitutional duty to consult the legislature before authorizing the use of military force and his government has said it does not intend to do so.

The nine-page intelligence summary, which included propriety French intelligence in addition to analyses of publicly circulated videos and information shared by allied intelligence services, was published on government Web sites on Monday evening. It asserts that Mr. Assad’s forces conducted attacks involving the “massive use of chemical agents” against civilian populations in several suburbs of Damascus on Aug. 21, and later mounted “significant ground and aerial strikes” with conventional munitions that were aimed at the “destruction of evidence” in those areas. The report gave no indication , however, as to the level of certitude of the conclusions presented.

“Our services possess information, from a national source, that leave one to think that other actions of this nature could again be conducted,” the report warned, though it provided no further detail. It said that none of the rebel groups fighting the Syrian government now possessed the “capacity to stock and use” such chemical agents.