Paris earned its nickname in the **19th century**, not for intellectual enlightenment (though that came too) but for **literal illumination**.
Visitors marveled at the "city of light" — a phrase popularized by journalists and travel writers. By 1900, electric arc lamps accelerated the lead.
Simultaneously, Enlightenment *philosophes* (Voltaire, Diderot, Rousseau) and salons made Paris the "capital of ideas." The nickname doubled: physical light + intellectual light. The 1889/1900 Expositions Universelles (Eiffel Tower, electricity palace) cemented both.
Today, the moniker lives in nightly illuminations: Eiffel Tower sparkle (5 min/hour), Louvre pyramid, Notre-Dame (pre-fire), Champs-Élysées, Seine bridges, Montmartre. The "City of Light" brand drives tourism, diplomacy, and self-image—Paris as beacon.
Other cities claim light nicknames (Lyon "Fête des Lumières," Hong Kong "Pearl of the Orient," Las Vegas "Neon Capital"). But **Paris owns the original, longest-held, most culturally embedded "City of Light."**