Paris neighborhoods

https://store.ricksteves.com/shop/p/paris-guidebook

or for budget shopping-- https://www.thriftbooks.com/w/rick-steves-paris-2011_rick-steves_gene-openshaw/302137/all-editions/?resultid=5c39f219-c5d1-4d44-9627-267c5c98f51c

should provide some pros/cons of the available choices

As Joe noted, the guidebooks all cover recommended neighborhoods. If you use the search function at the top of the page, you should find quite a few previous threads on the subject. The prevailing wisdom seems to be a place in the 1 - 7 arrondissements, since they are closest to the center of the oldest part of the city. Also look for a hotel in close proximity to a metro station.

It depends on what you are looking for but generally speaking Le Marais, Ile Saint Louis, the Latin Quarter and Saint Germain are often suggested. Here is a pretty good summary of many neighborhoods: https://thesavvybackpacker.com/city-guide/where-stay-paris-neighborhoods/

If you want to stay where there is a concentration of tourists, consider St Germain, Latin Quarter, or le Marais.

Two locations with an unusually large number of particularly American tourists are rue de Buci in the 6th and rue Cler in the 7th.

Should you like to break out and find an interesting neighborhood with lots of local activity and a plethora of transportation options, consider rue du Commerce in the 15th, Quartier Vavin in the 6th, rue Chomel in the 7th near le Bon Marché, and near rue de Richelieu in the 2nd. If you are active at night, the area around République might hold great promise.

Generally, as the transportation network is so comprehensive, anywhere in one of the 20 arrondissements (Paris), can work for you. It depends upon budget and interests.

By all means, if your goal is to stay in the proximity of other tourists, the Left Bank neighborhoods are the best, together with the lower numbered Arrondissements near the Seine. To explore more "French" neighborhoods, may I suggest that the 9th, 10th, and 11th Arrondissements are rich with cultural energy and down to earth liveliness. Fewer hotels, yes. Great restaurants and bars abound.

The Metro is everywhere, and for those rare pockets where a 2 block walk is necessary to descend into the ground, there are buses.

Buy a good guidebook (RS France/Paris or Lonely Planet) and go to town.

For a first visit to Paris, I agree with JHK’s advice. The closer to the river the better. Yes, there are tourists. You would be one of them. Those areas are central and walkable to many places you would likely want to see. Rick Steves loves Rue Cler, located in the 7th and near the Eiffel Tower. It’s inconvenient to almost anywhere else. And yes, I’ve stayed there.

How long will you be in Paris?

As other posters said, it really depends on what you want to get out of your visit and how you like to travel. I've been to Paris twice, planning on going again in October (hopefully). I personally like to stay closer to the river because that's where the sites are. My last two visits I stayed on Rue Cler in the 7th, which seems to be RS favorite area in his books. It's quieter and offers a much more charming experience than some other areas such as around the the Louvre or the Champs Elysees. It's very close to the Eiffel Tower, Rodin Museum, and Army Museum, and the bus and metro will take you everywhere else. For this next trip, I want to change it up and try a different neighborhood. I'm leaning strongly towards the Marais because I just liked the vibe of that area when I was there last, but am also thinking about the area around the Pantheon and Luxembourg Gardens. The RS Paris guidebook was just updated and is a very good resource, it has some nice city walks in different areas which are a great way to explore the neighborhoods you're not staying in.

We often travel to Paris and stay well outside the center. But for a first visit where you will want to be visiting the major museums and similar sights and enjoying the beauty of charming neighborhoods and strolls along the Seine, I would choose the 4th (Marais), 5th (Latin Quarter) or 6th (San Germain) and as close to the river as you can. From these spots you will be able to walk to many interesting sites and museums and they are lovely areas to stroll in the evening.

Two points:

The one time I stayed in the Rue Cler neighborhood, all I saw was a bunch of people with their faces buried in a Rick Steves' book. Also, It is not as close to many of the larger sights other than the Eiffel Tower.

Two, personally, I rarely use the metro. It is like tunneling underground rather than actually seeing the sights. I prefer to either walk, (which leads to a recommendation for areas near the river closer to the islands) or take buses. At least with a bus, you are above ground and can actually see the sights and neighborhoods when you have to take public transportation—rather than missing them completely when traveling underground.

I personally usually stay in the 2nd, 5th or 6th, 8th, 9th. The 8/9 mostly because they are closer to Gare Saint-Lazare, from which I personally usually exit or enter the city—but they are also nice neighborhoods in their own right.

I see bad news that affects every arrondissement. Paris is a city, not a resort with armed guards. However, Paris itself is relatively safe, very safe for tourists. The item of greatest concern for tourists is pickpocketing; particularly in crowded areas such as the métro, buses, museums, and other popular tourist venues.

Crime is a fact of life. In terms of overall risk, Paris is one of the safest cities of its size on the globe.

We have stayed in the 7th a few times and really enjoyed it. Would stay there again. Walking or Bus/Metro is convenient to almost anywhere.

I have enjoyed staying near Jardin de Luxembourg and the Pantheon. It is comfortable and reasonably close to the river.