NEW YORK (CBSNewYork) — The aftermath of the Paris attacks has left New Yorkers on edge, and a growing number of 911 calls coming in from people concerned about their surroundings.

As CBS2’s Dave Carlin reported Tuesday night, the directive, “If you see something, say something,” was heard as usual in the subway system in Brooklyn as people left the Nets’ game against the Atlanta Hawks.

READ MORE: 1960s Civil Rights Activist Robert Moses Dies At Age 86

But it had extra meaning for many, just four days after terrorists in Paris shifted from landmarks everyone knows to softer topics such as music halls and cafés.

Law enforcement officers have been answering more and more calls to 911, about such things as suspicious behaviors and abandoned bags and packages.

A suitcase at the NJ TRANSIT train station in Linden, New Jersey prompted a 911 call Tuesday. It turned out to be a false alarm.

But erring on the side of caution is the right way to go, said security expert and former FBI agent Manny Gomez.

“A lot of these things are going to be perhaps just paranoia or hysteria, but we still need the public’s eyes and ears and we need people to step up and say, ‘Hey, there is something happening here,’” Gomez said.

Earlier, crowds of Nets fans saw more police officers than usual as they entered the Barclays Center.

READ MORE: NYPD: Group Lighting Fireworks In Queens Attacked Man Walking Dog When He Complained About Noise

Some people said the police presence was reassuring – but not completely.

“The Paris thing has me on edge for sure,” said Jamaal Davis of Park Slope, Brooklyn.

On-edge can translate into vigilant. But a dark side surfaces in social media, where people can invent threats and spread misinformation.

Federal officials and the NYPD told CBS2 there are no known specific, credible threats for our area.

“People make up these stories all the time. You see them even without what happened in Paris. They’re always making up this stuff,” said Sara Dubin of Washington Heights. “I just try to like ignore it and like not think about it, because otherwise I won’t be able to go outside and I don’t want to like live in fear.”

Gomez said the key is alertness, not fear.

“We don’t have to be on edge. We don’t to be scared,” he said. “We just have to be alert as to our surroundings.”

MORE NEWS: See It: Ramapo Police Officer Helps Rescue Raccoon With Head Stuck In Can

Gomez said it is time to be extra alert – especially in malls and at big holiday gatherings.