Dublin's Dartmouth Square has been declared a special conservation area by the city council in a move that will block any development of the park.
The council has been in a legal dispute with businessman Noel O'Gara who bought the two-acre park and tried to open a car park there.
But the Architectural Conservation Area order passed this evening by Dublin Councillors means the park is now protected.
Owners of over 70 houses in the area will also face a number of planning restrictions imposed to preserve the character of the square.
From tonight, residents will not be able to put in PVC windows, use their front gardens for car parking or put satellite dishes on the front of their houses.
Meanwhile, a preservation order for 47 trees in the park is due to come into effect later this month.
The council has also obtained a compulsory purchase order for the park.