There is also a persistent sense in Paris government offices that France can’t count on the U.S., either. President François Hollande viewed as a betrayal Mr. Obama’s decision in 2013 to abort planned joint airstrikes against the Syrian regime. Since then, Mr. Hollande has repeatedly pointed to that flip-flop as a reason for the rise of Islamist radicalism in Syria.

Now, it is France rather than the U.S. that is paying the costs of Washington’s regional “disengagement without taking into account the consequences,” said Gilles Dorronsoro, a professor of political science at Sorbonne University in Paris.

“There are almost no refugees in America, and, for now, no terror attacks,” said Mr. Dorronsoro. “The stakes, or at least the perceived stakes, for the U.S. are not the same. The French will discover soon that no one will change their state policies just because 130 people have died in Paris.”