PARIS—The world seems awash in sympathy with France’s tragedy, from candlelight vigils to stadiums illuminated in tricolor. But, when it comes to action against Islamic State, there is growing fear in Paris that France may be in this fight dangerously alone.

French officials are particularly frustrated with their European Union partners over what they see as insufficient cooperation in intelligence, security, and defense. “Everyone must understand that it’s urgent for Europe to recover, to organize itself, and to defend itself against the terrorist menace,” French Interior Minister Bernard Cazeneuve said this week.

In one way, the U.S. has responded much more quickly than France’s European partners after the Nov. 13 attacks, boosting intelligence-sharing with Paris. But Washington hasn’t signaled that a more determined military effort against Islamic State lies ahead. President Barack Obama reiterated this week that the current U.S. approach of limited military engagement is working, and ruled out the use of ground troops.

French officials and politicians worry that the U.S. is underestimating the threat Islamic State poses to the international community.

“The goal of the attacks in Paris was to destroy our values, the values shared by the U.S. and France. And without a doubt we need for the American people to understand that this is also their war,” said Frederic Lefebvre, a member of the defense committee in the French National Assembly and a former minister. “We need to have allies that are strong, and that act.”

In September 2001, America’s allies—such as France—instantly offered their help under the North Atlantic Treaty Organization’s Article 5, which provides for collective defense.

Paris, which described the Nov. 13 shooting and bombing spree that killed 130 people as “an act of war,” hasn’t asked for NATO assistance, invoking instead the mutual-defense obligations of the European Union. The response has been lukewarm, at best. Even France’s request to loosen fiscal rules so it could beef up its army and police to protect the country against Islamic State has been met with noncommittal statements from Brussels, so far.

“In Brussels, the symbolism of solidarity with France has been lacking from the beginning. We are on our own, and we are counting our friends,” said François Heisbourg, an adviser at the Fondation pour la Recherche Strategique think tank and a former senior French diplomat.

No other European country has joined France in airstrikes against Islamic State in Syria so far, though British Prime Minister David Cameron has called for a parliament vote to authorize such an operation. In Iraq, too, no additional European countries entered the air campaign that is being conducted by France, the United Kingdom, Belgium, Denmark and the Netherlands as part of the American-led coalition against Islamic State.

Recognizing the challenge, Paris has asked for something simpler: help in its campaign against Islamist radicals in Mali—where 27 people were killed Friday during a siege by gunmen in the capital—and in other West African nations. That would allow the French to free up elite troops to concentrate on Islamic State. But on that front, too, only Ireland has offered to send a “small” number of troops so far.

“Why is France targeted more than others? Because the Germans don’t want to move a finger, leaving us all alone in the battle against international terrorism,” said Mr. Lefebvre, the lawmaker. “Many countries avoid military action because they don’t want to run the risk of becoming targets themselves, and because it is costly.”

Germany has been providing weapons to Kurdish fighters against Islamic State in Iraq but so far has ruled out a more direct military role.

Even though France asked, following the January Charlie Hebdo attacks, for the sharing of information on air travel bookings, the European Parliament scuttled the decision over privacy concerns. Mr. Cazeneuve, in his address this week, noted that no European nation tipped off Paris about the movements of Abdelhamid Abaaoud, the architect of the Paris attacks, across the continent from Syria.

“Except for Britain, we can’t count too much on European solidarity,” said Axel Poniatowski, deputy chairman of the National Assembly’s foreign-affairs committee.

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.”