1st arrondissement in Paris. Good location ?

In case you don't know how they work the Paris arrondissement starts with 1 (oldest/most central) and spirals clockwise outwards from there. In general yes 1 is a good, central area. Suggest you use Google to explore the area around the apartment. Enter the address is google, click on the small map that comes up. You can search things like nearest metro, cafe, grocery store, etc or directions from/to the address to various points like sights to see. It will give you walking or public transport routes. You can also use Google earth (click satellite view) and explore the area visually as if on foot. Keep in mind that often the photo crew takes pictures during quite early morning hours so it may look at bit different during normal hours.

Warning about Montmartre, parts of it are a bit sleezy (sex shops, etc), others boring, and the area near the cathedral teeming with street artists nagging you to have your picture done. Once was enough for me and I wouldn't take kids there.

Also: be sure to make sure that any apartment you do rent has the legally required Registration Number.
It's either 13 or 14 digits long, I can't remember.
There has been a lot of discussion about it on these forums in the recent past.
Otherwise, you run the risk of having nowhere to stay when you arrive, or neighbours complaining about rentals while you are there and being evicted, etc.
Check to see if there grocery stores nearby when you rent an apartment.
YELP or Google maps can pinpoint those for you.
You might want to cook!

That would be a very good location for sightseeing, close to a lot of major sights and Metro lines to others. In general, the 1st would be more expensive than less central areas, but maybe you got a bargain. I agree with the advice to look for nearby services on Google Maps, eyeball the neighborhood on Google Earth's "street view" feature, and make sure your apartment has the required registration number.

Montmartre is mostly very nice, with some sleazier parts around Place Pigalle that you can just pass by quickly -- maybe blindfold the kids? ;-)

In addition to cooking there are some interesting takeout options. Lots of Monoprix stores with groceries and prepared foods. They range in size from full department stores to little mini marts.

I'm researching an upcoming trip I found a couple of other options. La grande epicerie has at least two locations with awesome food courts (takeout) plus several restaurants. The pictures on trip advisor look amazing.

There is also a chain called Picard Surgeles that specializes in frozen foods. Everything from appetizers to desserts. Cooking in a strange kitchen without your usual stock of staples, spices, recipes, etc can be a challenge.

The 1st is generally a fine location for 1st-timers; we've stayed there. If you'll be located near Jardins du Palais Royal, then you'd be close to Jardin des Tuileries and the Louvre, and easy walking distance for any number of other attractions. It does tend to be a more expensive location than others of the close-in arrondissements.

As far as "quaint" neighborhoods, pretty much all of historic, central Paris falls into that category, as the definition goes. LOL, I have a personal issue with the term as it smacks a bit of tourist-described "cuteness" but I'll cheerfully chew a lip and let it go. HA! Your children may also be able to tolerate just so much "quaint" neighborhood ambling before needing something a bit more to their preferences. The "obvious things" in Paris? Which of those do you have on your list?

Montmartre is OK as long as you know what it is you want to see, and understand that parts of it are crowded tourist magnets. We loved our wander through Cimetière de Montmartre as it was blissfully free of the mob plus is the resting place of any number of notables such as Vaslav Nijinsky, Alexander Dumas, Edgar Degas and Hector Berlioz. I took my saxophonist husband there to see the tomb of the inventor of his instrument: Adolphe Sax. Young folks can find Parisian cemeteries to be fascinating crawls through spooky, crumbling mausoleums and evocative sculpture.

You don't need the Metro to visit the Marais from the 1st as it's not that far away. We also walked to Montmartre from the 1st - and enjoyed the journey - but will admit that it's probably a longer trek than most visitors want to do on foot. Depending on your must-see list, you might not need the Metro much at all; Paris is such a wonderful city to explore from the sidewalks!

I don’t know how it is now, but many years ago we took out 13 year old daughter to the Montamarte area and we were totally unprepared for passing sex shops. So... just be aware.

Just fyi, it’s Montmartre.

The 1st isn’t the most central, Notre Dame Cathedral is the center of Paris, but it’s darn close. It’s not the quaintest area, that would be the Marais, Ile St Louis, Ile de la Cité (where Notre Dame is), the 5th (Latin Quarter) and the 6th (St Germain des Près). But it’s fine.

We've avoided the 1st because of a perception that we get more for our lodging euro/dollar in the close-in arrondissements other than the 1st, for example, the 5th or 7th.

It’s a nice central location.

Very good.

Montmartre is the neighborhood we always stay in. Use metro station Blanche which is by the Moulin Rouge and walk straight up hill on Rue Lepic to wander the area working your way to the Sacre Coeur. Pick up something simple to eat. For years there was a roasted chicken shop on Rue Lepic that we have enjoyed take out. Enjoy the activities on the church’s steps as the sun sets. This ranks just below a boat ride on the Siene for a sunset activity and it’s free. Backtrack to Blanche metro through the upper streets taking a right turn at the base of the steps and funicular. There is a deep metro Abbesses at the Place De Abbesses which shortens the walk. Don’t go straight down hill from the church steps to Place Pigalle or Anvers metro as shown on the RS France tour book. That area is sketchy feeling. Use a real Paris map. There is a lot of people and no “iffy” feelings up higher on the hill. Remember the shortest route shown on the RS guide book will direct you to the shadier part of town.

Two comments
We had a lovely day in Montmarte last fall, meeting Paris Walks. Delightful lunch at top of hill near a park. I must be blind but saw no sex shops. Highly recommend Paris Walks.

Second, you may be near a Metro but do check to see if that line has good connections.

Enjoy

The location is central but not necessarily quaint or quiet. The stretch of Rue de Richelieu from Rue des Petits Champs to Place André Malraux is actually a rather busy and noisy area. My children did not like the Jardin du Palais Royal mainly because they could not play on the grass. A few years ago, I gave some older relatives a trip to Paris and put them up at the apartment hotel at the corner of Rue de Richelieu and Place André Malraux. They loved the location but then again they went to the Louvre just as I thought they would almost every day that they were in Paris. They also loved that the closest metro station to their hotel was served by line 1.

Thanks to everyone for all those answers !

Hi and thanks for those answers once again, we finally made a reservation for an appartment with air con (2 splits in the appartment, it should work ok), The airbnb (and yes it does have a registration number)  is on Mandar street in the 2nd arrondissement, hope it will be ok....

Rue Mandar looks nice enough on Google Earth, with a variety of cafes and restaurants. There's a bakery at one end, on rue Montmartre, and a "Palais de Fruits," apparently also with vegetables, at the other end on rue Montorgueil. Several Metro stations are nearby in different directions. You should do fine there.

For me, it’s a more enjoyable area than the 1st, and rue Montorgueil (pedestrian only) is fabulous. Also, air splits work really well.

I too like this area better than your initial choice. In the summer of 2017, I stayed one block away from Rue Mandar on Rue Bachaumont and really liked the area. The first time I ever saw a dog in a stroller was at the corner of Rue Mandar and Rue Montorgeuil — it’s a great area. There are a number of bars in area (our favorite was the Experimental Cocktail Club) but it was not very noisy.

Are the 13/14 digit registration numbers at the end of a listing for apartment rentals unique to Paris or do other rentals needing them as well?

Short term rentals are controlled in any city with a population in excess of 200,000 as well as all the communities surrounding Paris. The registration numbers consist of 13 digits. Those within Paris start with 75.

Short term rentals displaying a registration number are likely to be legal but a registration number itself is not a guarantee. Rentals without a registration number are very unlikely to be legal rentals. Generally, qualifying rentals in Paris are those offered by a primary owner/occupant renting his home up to 120 days a year. Nice limits rentals to 90 days a year but an owner may rent up to 3 apartments, none of which must be his primary residence.

The rental laws originate with the French government but cities are given some discretion as to how they are implemented. The government's objective is to preserve, to the greatest extent possible, the ever shrinking supply of housing for city residents. Paris has significantly stepped up enforcement of rental laws, owners can be fined up to 50,000€ for each occurrence of illegal rental activity. Increased enforcement and dwindling revenue due to Covid and confinement rules have combined to cut the number of available properties as owners sell or convert apartments to long term contracts.

Anyone considering short term rentals in Paris should maintain backup options in the event that their planned accommodations are redrawn from the short term marketplace.