Complex sentence: He converted his personal parking space--the reserved parking space next to City Hall that is one of his mayoral privileges--into a mini park and it is now decorated with tree stumps and benches for a public open use.
Split into simpler sentences: He converted his personal parking space--the reserved parking space next to City Hall that is one of his mayoral privileges--into a mini park. It is now decorated with tree stumps and benches for public open use.