Bicycle on sidewalk rules- Is there a rule about which direction you’re only allowed to ride?

I bike to work every day and use the sidewalk when there’s a sign that allows bicycles. However, my coworkers warned me that police are getting stricter and said I should only ride in the same direction as traffic, even on the sidewalk. Now I’m confused. To add, only one sidewalk has the permit sign while the opposite side doesn't. Is there actually a rule that bicycles on sidewalks must follow the same traffic direction, or can you ride both ways if the sidewalk allows bicycles?