PARIS — Since the devastating Nov. 13 attacks in Paris, the French police have offered only a fragmentary outline of their response and of how they deployed antiterror teams and other forces. The somberness and solidarity in the weeks since have muted public criticism. No review of the police’s performance has been announced.

Yet accounts from survivors and police officials, as well as the analysis of outside experts, make clear that there were substantial periods when the terrorists operated with little or no hindrance from the authorities, and that France’s top-heavy chain of command, which has diminished neighborhood patrols in favor of specialized units, contributed to delays.

The first officer to reach the worst of the carnage — at the Bataclan concert hall, where 90 of the 130 victims that night were killed — got there roughly 15 minutes into the attack. Armed with only a service sidearm, he managed to stall the killing by shooting one attacker, blowing up the terrorist’s suicide vest while sparing the victims around him.

Yet the officer was ordered to withdraw in favor of a more specialized antiterrorism unit, which arrived half an hour into the assault after initially being sent to sites where the violence had already ended. Another specialized unit nearby was apparently never deployed, according to a French news report.