Why is Paris nicknamed "The City Of Lights"?

Etymology: PARIS
Wikipedia

The name Paris derives from that of its inhabitants, the Gaulish tribe known as the Parisii.  The city was called Lutetia (more fully, Lutetia Parisiorum, "Lutetia of the Parisii"), during the Roman era of the 1st- to 6th-century, but during the reign of Julian the Apostate (360–363) the city was renamed Paris. It is considered that the name of the Parisii tribe comes from the Celtic Gallic word parisio meaning "the working people" or "the craftsmen."

Since the mid-19th century, Paris has been known as Paname in the Parisian slang called argot (Moi j'suis d'Paname, i.e. "I'm from Paname"). The singer Renaud repopularized the term amongst the young generation with his 1976 album Amoureux de Paname ("In love with Paname").

Paris has many nicknames, but its most famous is "La Ville-Lumière" ("The City of Light"), a name it owes first to its fame as a centre of education and ideas during the Age of Enlightenment, and later to its early adoption of street lighting. Paris' inhabitants are known in English as "Parisians" and in French as Parisiens. Parisians are often pejoratively called Parigots, a term first used in 1900 by those living outside the Paris region, but now the term may be considered endearing by Parisians themselves.