On a blustery day last February, I navigated my bicycle down to the Seine River. Along the quai d’Austerlitz floats a slightly dilapidated barge, where I had an appointment with two architects, Michel and Julien. They’re in charge of restoring Paris’ first-ever floating monument, a river boat called the Louise-Catherine. The goal of our rendez-vous? A private tour of this unsinkable memorial to fascinating times past.