I think there's a lot of details around us that we take for granted so much that we don't even notice or question them anymore. Real life is inspiration, don't ya know.
A little Wikipedia research tells us a lot in a few seconds (the French article is longer). Le Chat Noir was one of the first (if not the first) nightclub/artist salons in Montmartre (ya know, where le Moulin Rouge was, where artists live and die, where street performers still dazzle tourists on the steps of the Sacre Coeur church, etc.)
The name on the poster, Rodolphe Salis, is that of the owner. They say he named it after a stray cat found on the sidewalk while they were doing renovations. He was the first to have the idea of bringing in a piano, basically creating the cabaret music style. Salis is quoted as saying "The Chat Noir is the most extraordinary cabaret in the world. You rub shoulders with the most famous men of Paris, meeting there with foreigners from every corner of the world." It became a favorite haunt of painters, musicians and poets.
The cabaret closed after Salis' death in 1897. The weekly review the cabaret published, Le Chat Noir, continued for a couple years. The iconic name has been used for cabarets, bars, cafés, reviews, and plays around the world. The poster, created by Théophile-Alexandre Steinlen as an advertisement, is now such a common place Paris image that we don't even ask what it is.
History and stories surround us, even in that stupid gift shop keyring! This makes me think of a fellow SCBWI France member, Sarah Towle, who created an interactive StoryApp iTineraries, called Beware Madame the Guillotine! It's a tour of Paris, with a story. Talk about really noticing the details and understanding what you're seeing; that's real life writing!! I haven't done it yet (can't wait!) but go to Time Traveler Tours to find out more.
Try to find some well-known object or image to question and research - I'd love to hear what you've discovered!