Possible Clues:

• Some Louvre paintings
• 'Luncheon on the Grass' and others
• Some Musée d'Orsay works
• Numerous Louvre works
• Many Louvre works
• National Gallery attractions
• Some Impressionist paintings
• 'The Fife Player' and 'Olympia'
• "The Luncheon on the Grass" and "Olympia," e.g
• Some Musée d'Orsay works