Quick Tip: The Batobus
If you're not into crowds, and waiting, and aren't a tourist, it might not be your cup of tea during the summer months. Since I live near Jardin des Plantes (the last stop) I have the pleasure of seeing it whenever I chill out by the Seine. It's always packed and the line is super long. I once saw it pass by four or five times and it never made the stop for the long line of people waiting because there were just too many people already on it. But it's an interesting concept and a much more scenic way to see Paris. And best part they have something called "the Batobus Treasure Hunt". It's only in French though :/
Their website:
And for a true cruise experience complete with tour guide voiceover: