If you're on one of GCT's excellent river cruises, you might want to try a museum near the Eiffel Tower. It's the Musee de Quai Branley, which features collections of art from African, Asian, Pacific Island and American indigenous cultures. Fascinating! The museum itself is beautiful. It was designed by the architect Jean Novel and gives the feeling of being in the cultures. Plus ..... and this is important ..... it's never crowded.
There are two restaurants, Cafe Branly, for salads, sandwiches and snacks and Les Ombres, upscale with incredible views of the Eiffel Tower.
If you've already seen the major Paris museums, this may be a good choice.