We traveled with 7 travelers on The Traveling Professor's small group tour to Paris.   Here are my observations:

Professional, Licensed Tour Guides:   We used 3 different guides.   Each one was better than the other.  I think using a professional and licensed tour guide makes all the difference in the world.  The interaction between the guide and travelers is far, far better than any tour book (including mine, LOL) or phone app.

Public Transportation:  Although we did use the metro and RER train, most of the time we used the bus.  It allowed us to go on OUR schedule.  The bus requires no stairs and gives a better perspective of Paris as opposed riding in a hole in the ground (the metro).  Each traveler had a Navigo Decouverte card allowing unlimited transportation on bus, metro, funicular, and RER train all over Paris including airport and Versailles.

Limo Pickup from Airport:  Boy, did our jet-lagged travelers love to be greeted at the airport by a driver who whisked them directly to the hotel.

Crowd Avoidance:  We successfully avoided the MASSIVE crowds in Paris by going to attractions at the right time and the right days.  My extensive experience of traveling to Paris has taught me when to visit.   For instance, we used the Paris Museum Pass giving us unlimited, no-wait-in-line admission.   Our professional guides know the "secrets" of getting around in museums, we visited the Louvre at night where crowds are 1/3 of what they are during the day.   We accomplished more than the typical travelers does because we don't waste our time waiting in line and we know when attractions are least crowded.

Meals:  We prefer good, authentic restaurants offering good meals at reasonable prices.  Although most times we ate at French spots, we threw in a Mediterranean and Italian place in and our travelers really appreciated it.   House wine is as good as any and cheaper than Coca Cola or beer.

Perfectly Located Hotel:  Let's face it, Paris hotel rooms are small, regardless of the price of the hotel.  So on our small group tour to Paris I concentrated on selecting a hotel in the center of the historic area.   It was clean, comfortable, quiet with friendly service.  The location was unbeatable.