Florida law requires that arrests be made upon probable cause. If there is no probable cause for an arrest then the arresting agency and the police officer may be subject to an action for false arrest and false imprisonment.
Also with respect to misdemeanor charges, in order for a police officer to physically arrest a person for a misdemeanor in Florida, the misdemeanor must have been committed in the presence of the officer. There are some exceptions such as in domestic violence cases. However, the officer still needs probable cause to arrest the person.
In typical misdemeanor cases, if the officer didn't witness the incident, he may issue the person a "PTA" or promise to appear citation if the officer had probable cause to believe a crime had been committed. If the officer physically arrests a person for a misdemeanor not committed in his presence, he/she may still be liable for false imprisonment and unlawful arrest.
The arrested person may have a civil case for money damages in such cases. The most important criteria aside from actual liability is whether or not the person has ever been arrested before. A person who has never been arrested before stands to be more traumatized than someone who has.
You have 3 years from the time of the unlawful/false arrest to bring the action against the officer and government entity.