Phoenix Park is 3.5 times larger than Monaco.
Area: 2 km2 World Factbook
Population: 30,508 (July 2014) World Factbook
Monaco, officially the Principality of Monaco, is a sovereign city-state and microstate, located on the French Riviera in Western Europe. It is bordered by France on three sides; one side borders the Mediterranean Sea. Wikipedia
Area: 7 km2 calculated
Phoenix Park is an urban park in Dublin, Ireland, lying 2–4 km west of the city centre, north of the River Liffey. Its 11 km perimeter wall encloses 707 hectares, one of the largest walled city parks in Europe. Wikipedia