why was it called so?
Because of its leading role during the Age of Enlightenment and more literally because Paris was one of the first large European cities to use gas street lighting on a grand scale on its boulevards and monuments.
Paris
Paris is often referred to as the 'City of Light' ("La Ville Lumière"), both because of its leading role during the Age of Enlightenment and more literally because Paris was one of the first large European cities to use gas street lighting on a grand scale on its boulevards and monuments. 
where is paris france located on the world map It is located in northern central France, in a north-bending arc of the river Seine. is the city a capital of france? Yes what is its estimated population? 2,148,271, as of 2020 how did the name of the city derived at? From its early inhabitants, the Gallic Parisii tribe. who are the aforementioned tribe? UNANSWERABLE is the city also referred to as the 'city of light'? Yes
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Paris [SEP] Etymology
Gas lights were installed on the Place du Carrousel, Rue de Rivoli and Place Vendome in 1829. By 1857, the Grand boulevards were lit. By the 1860s, the boulevards and streets of Paris were illuminated by 56,000 gas lamps. Since the late 19th century, Paris has also been known as "Panam(e)" () in French slang. Inhabitants are known in English as "Parisians" and in French as "Parisiens" (). They are also pejoratively called "Parigots" ().