PARIS – U.S. President Barack Obama's decision to seek the green light of Congress before any intervention against Bashar al-Assad's regime could spell trouble for the French government.

Last week's ramping up of accusations — both by Paris and Washington — against the Syrian government's alleged use of chemical weapons seemed to indicate that strikes against military installations inside Syria were imminent.

And yet despite intense consultations between the two countries, Obama's announcement on Saturday caught Paris off-guard. It also risks leaving President François Hollande isolated in his willingness to quickly "punish" the Syrian regime, as he indicated in a Le Monde interview on Friday. This isolation is even more striking considering that France had become the White House's most important ally on Syria after the British House of Commons' surprise rejection of any UK involvement in a military action.

At the Élysée Palace, presidential aides are trying to minimize their embarrassment by underlining the fact that Obama informed Hollande of his decision to ask the Congress' approval during their phone conversation on Saturday. The 40-minute call took place just before Obama's speech.

One official close to the French president insisted that in this conversation — the second in two days between Obama and Hollande — "they both reaffirmed their growing determination to act, given the convincing elements of information they have about the existing production of chemical weapons in Syria." French officials also point out that Hollande told Obama that he had called Parliament for an extraordinary session on Wednesday to address the situation.

"Not backpedalling"

However, Foreign Ministry officials did not hide the fact that they were disconcerted by Obama's announcement. A source close to Foreign Minister Laurent Fabius said, "It's not necessarily what one could have expected, considering the vigor of John Kerry's speech," referring to the Secretary of State's scathing words on Friday to denounce the "crime against humanity" committed by the Syrian forces on Aug. 21.

The source added, "We understood then that the American decision to intervene had been taken."

Still, both the Presidency and the Foreign Ministry consider that the situation has not fundamentally changed. A diplomat pointed out: "Obama didn't say no, but rather explained that he needs the political legitimacy of the Congress to intervene. That's understandable given the state of public opinion in the U.S. and the scars left by 10 years of American commitment in the Middle East. If we must wait, we will. This is not backpedalling. The decision in principle to act together to punish the use of chemical weapons is not in question."

On the other hand, if the American Congress follows the path of Britain's House of Commons and rejects participating in a military intervention, France will have to completely re-examine its strategy. The Foreign Ministry source admitted that "going there alone would make no sense."

In other words, the climate has indeed changed over just a few days. After a notably tough speech made to French ambassadors on Aug. 27, the pro-intervention stance of Hollande and his aides now has given way to a certain skittishness about the fate of the international coalition that had been lining up against Bashar al-Assad's regime.