The prettiest feature of this lush little square is the imposing 19th-century fountain and the park surrounding it. There used to be an opera house where the square is located now but it was torn down in 1820 after a member of the royal family was murdered here.
Wikipedia (French) https://fr.wikipedia.org/wiki/Square_Louvois
Address 4 Rue de Louvois, Paris 75002, France
Coordinates 48°52'4.704" N 2°20'15.266" E