LGBTQI+ scene
Paris concentrates one of the densest LGBTQI+ scenes in Europe: ~140 documented LGBT businesses (bars, clubs, hotels, restaurants, shops) according to a 2004 count. Le Marais takes most of it: 3-4 streets with 40+ venues within a 5-minute walk. Classic bars (Open Café, Cox, Duplex) and the bookshop Les Mots à la Bouche (now in the 11e).
Outside the Marais there are emerging secondary poles: Pigalle/SoPi (young queer), Bastille/11e (trendy nightlife), Belleville (multicultural queer). In the 90s Paris concentrated 46% of French gay men, according to Wikipedia itself.