You don't need to stay safe from anything. It is maybe one of the safest cities in Italy.
In some places throughout the city, as with anywhere on the planet, it is possible to trip and scuff your knee, or maybe sprain an ankle god forbid!. While in Forli, be sure to never walk with scissors or a knife because accidents can happen. If you do get lost in the city make sure you have ample water on hand because dehydration is never good for anyone. It is actually bad for all things since everything on earth revolves around water. What else, what else....oh, lock your door at night as sometimes when a person has too much vino they might try to walk into the wrong room and that is just awkward.