I offer walks around some charming quiet streets, alleys, and areas of Paris, which are often unknown of a lot of tourists. Those places might not be as beautiful as the Louvre for example, but I believe they have their own charm and atmosphere. That's why they should be seen, because they make Paris so unique.
But I can obviously show around the common monuments and museums, from the most to less visited, for a day or two.

However Paris doesn't only refer to the city, but also to its region. Paris region is easy to reach by public transports, which is perfect for day trips or even afternoons. A lot of places outside of Paris are very nice and enjoyable for their local historical heritage or their nature. That is why I think that places such as Provins, Fontainebleau, La Roche Guyon etc... are good to be seen!

Also, I can pick small groups of people from the airport and take them to their accomodation (by public transports), and help them have some points of reference, and guide them in their living area.

Anyway, be curious and feel free to explore Paris' streets and areas, you might find something interesting. That's my advice.