In its 117 years, the Ritz Paris has been more than a backdrop to world events — it has figured grandly into them. Its gossip-filled lobby was Marcel Proust’s inspiration; its cocktail bar a hub for French resistance during the Nazi occupation; its foyer a paparazzi magnet that Princess Diana traversed before her deadly car ride. But while the fabled luxury hotel on Place Vendôme has always been an independent icon, its decaying standards told another story. In 2011, the French tourism ministry humiliatingly left the Ritz off its list of ‘‘palaces’’ (a classification for five-star hotels of special character), compelling the hotel’s owner, Mohamed Al-Fayed, to upgrade. Now, after three years and an estimated $227 million renovation by the architect Thierry Despont, the 142-room Ritz reopened a few weeks ago — complete with upgraded suites, a spacious new fitness center and, unsurprisingly, an untouched Bar Hemingway. A recognition, perhaps, that while time and technology march on, history is one luxury that can never be replaced.