If you're planning a night at the opera, Palais Garnier in 9th Arrondissement should be top of your list. If you want to go again, Philharmonie de Paris is another great choice in Paris, and is actually not far from Palais Garnier.
Place de l’Opéra is worth passing through for a few pics when in 9th Arrondissement. Our travelers also love the cathedral, art galleries, and museums in the area— your sightseeing tour starts here. Paris has lots of other popular landmarks you might want to visit such as Notre-Dame and Arc de Triomphe.