Paris
FranceParis has Europe's densest cat-friendly hotel inventory and a long cafรฉ culture that quietly welcomes a calm cat in a soft carrier. The Pรฉre-Lachaise cemetery is a famous resident-cat colony (300+ cats fed by city volunteers), the Cafรฉ des Chats and Le Cafe des Chats both let you visit cats while travelling with your own, and most boutique hotels have window-screens that prevent the dreaded "cat-out-the-window" scenario.
Boutique 5-star tucked into a private garden in Montmartre, cats explicitly welcomed (the resident hotel cat is well known). Window screens on all rooms, no balcony access, quiet residential street with zero traffic noise.