ISIS claims Raqqa as the capital of its so-called caliphate.
On Monday, France targeted a command center, a recruitment center, an ammunition storage base and a training camp in the city, the French military said.
On Sunday, the air force struck similar strategic targets in multiple sorties, reinserting France, a partner in the U.S.-led coalition striking ISIS from the air, into the battle against ISIS.
Many bombs, few killed?
A group of anti-ISIS activists in Raqqa reported 24 bombs dropped and 30 explosions overnight into Monday. Mostly the suburbs were hit, but in the city, the stadium and the museum were also struck, said Raqqa is Being Slaughtered Silently
ISIS uses the museum and the stadium as jails. Its headquarters are also in the stadium, the activists said.
On Sunday, 12 aircraft dropped 20 bombs on ISIS positions in Raqqa, destroying all targets, France's Defense Ministry said.
But French bombs may have killed few of the militants. The Islamist terror group has withdrawn from its sites in anticipation of the retaliation, Raqqa is Being Slaughtered Silently
said. Streets have been empty, markets less crowded.
No civilian casualties have been reported, the activist group said, and the civilian population does not seem particularly worried.
The activists said there have been ISIS casualties but could not say how many.
An ISIS media wing has said there were no casualties Sunday.
Also on Monday, French Interior Minister Bernard Cazeneuve said that "war" had been declared on France and that "anybody who attacks the Republic, the Republic will fight back."
"It is not they who will destroy the Republic. The Republic will destroy them," he said.
France has been part of the U.S.-led coalition of nations fighting ISIS from the air, but after Friday's attacks that killed 129 people
and wounded more than 350 others, France has flown more sorties.
ISIS has claimed responsibility for the attacks, which France's President described as "an act of war."
Military analyst: Strikes are 'symbolic'
A senior Obama administration official said that the United States was "working closely with the French to develop targets."
The U.S. military probably handed over a list of targets the coalition was planning to strike to the French to let them fly the sorties, said retired Lt. Gen. Mark Hertling, a military analyst. "These target packages were already in folders, as they're called, and I'm sure the central command handed them over to the French fighters to attack for the symbolism of France being back in the fight."
The timing of the new airstrikes probably is no coincidence, analysts said.
"Clearly, it's a military activity, but it really sends a very strong political message, and it's all for internal consumption within France," said retired Maj. Gen. James "Spider" Marks, a CNN military analyst. "This is very visceral."
ISIS in Raqqa was also the target of retaliatory airstrikes in February.
Two days after news emerged that the group had burned a captive Jordanian pilot to death, the Middle Eastern nation hit back
. At the time, ISIS posted photos of the destruction from the Jordanian airstrikes, and the activist group Syrian Observatory for Human Rights said 10 militants had been killed.