Fire code is a difficult thing at times for the un-indoctrinated, but when it comes to exit pathways it is clear and specific. We discussed design issues about numbers of exits and width of them based on the occupancy of the building. Once these are in place and the building is open, it is up to the tenant to keep them visible and accessible.
In general, the hallways or pathway to the exit must remain un-obstructed. One may not diminish the width of an exit with any object. No trash cans, no big plants, no small plants, nick-knacks or doo-dads allowed. Nothing you could walk into or trip over. The reason is fairly simple, when the fire occurs the people in the building may be disoriented, blinded by smoke or simply making a hasty retreat to the outside. You, as the person responsible may not hinder their egress. Your job is to make it easy to escape from harm.