Me and my wife found this by using TripAdvisor, but unfortunately I am dumb and didn't book it correctly. Luckily, the guys there are super nice and still fit us in. Our guide Nicol was incredibly knowledgeable about the city and about fun stuff to do. From the history of the city itself, to fun art facts (space invaders in Paris), and where to eat and shop.
They give you a great list of interesting things to do at the end of the tour, so we recommend doing what we did. Do this tour at the very beginning of your Paris trip and you will get a great idea for how the city really is. And then with their help, you won't be bored at all the rest of the time. They have so many great ideas for things to do in the city.
Don't get scared off by the fact that its a bike ride in a new city, they keep you safe. Just stick with them. However, don't expect a huge workout. Our guide would take us for a few minutes, and then stop to give us some history on the area and really let us soak it all in. It was perfect. BEST 30 EUROS SPENT IN PARIS.