San Francisco Police Chief Greg Suhr said the city is on "heightened alert" because of the series of attacks that thrust Paris into chaos on Friday.
The chief said his department has checked in with all of the city's foreign consulates, asking them to report any suspicious activity.
"At the immediate onset of the coordinated attacks in Paris we went on heightened alert," Suhr said. "All officers have been deployed and there will be a heavier presence anywhere we have significant crowds in San Francisco."
All available police officers are on duty, Suhr said, and they're asking everyone to report anything suspicious to law enforcement.
"There will be a heavier presence everywhere we have significant crowds in San Francisco, certainly all the other entertainment districts, as that appears to be an area of interest in these coordinated attacks," he said.
Suhr stressed there has been no specific, or general, threat against San Francisco and that the heightened alert was called for out of an abundance of caution.
He also said the police department had checked in with the FBI to "cover all bases."