Surveying the glittering collection of Napoleonic objects laid out in an auction hall near Paris, Bruno Ledoux said he had a good reason for his interest in a set of baby clothes belonging to Napoleon Bonaparte’s son.

“You see, I have a palace,” said Mr. Ledoux, who owns not just a palace, but the palace of Napoleon II, Napoleon’s son, on the outskirts of Paris.

Mr. Ledoux, one of France’s biggest Napoleon collectors and owner of the newspaper Libération, had come here on Saturday to one of the largest auctions of Napoleon memorabilia ever held, looking for items for a museum he is creating.