The Musée Carnavalet is the city's own history museum, and much of it is the physical debris of Paris. Dugout canoes pulled from river mud at Bercy, old shop signs in painted wood and forged iron, a jeweller's shop designed by Alphonse Mucha, the bed Marcel Proust wrote in. Whole rooms lifted out of demolished houses stand rebuilt inside, so you walk through them rather than look at them. The building is salvage too, down to a stone arch of 1555 carted here from the Île de la Cité.
The museum exists because the man demolishing old Paris decided somebody should keep the pieces. While Haussmann's crews cut boulevards through the medieval streets, the city bought this Renaissance mansion on his own advice, to hold whatever the wrecking turned up. Then that first collection burned: it was stored in the Hôtel de Ville, and Commune fighters set the city hall alight with everything inside it. So the museum opened with almost nothing of its own, and nearly everything you walk past arrived later as a gift. It holds more than six hundred thousand objects and shows fewer than four thousand.