Arriving late at Paris Lyon

Just being cautious. Nothing wrong with that. I think you will be fine. We have been in that station in the evening but not as late as you might be. It is a relative small station with a short walk to the front and the taxis. Second, you should have a good flow of other passengers headed to the front of the station so get in the flow. The last time we were there the police presents was high but don't know if that is normal or not.

Gare de Lyon in Paris is totally fine even late at night - nothing more than "usual city precautions" needed.
The taxi line there can be a drag, though. There's no real workaround except patience.

I agree this is one of the less bustling stations, but this is a major city of the world, and one that depends on train travel. You simply need to exercise the usual street-savvy, like looking for the signs to the taxi stand, and not responding to un-uniformed individuals (like at my Newark Airport at home in the "safe" USA) who nod and ask, "Do you require transportation?". It's also better to "look like" you can handle your luggage, since there are virtually no "porters" anymore.

Have you prepared a slip of paper with the name and address of the hotel, in case your driver has particularly weak English? (Honestly, that's less of a problem these days.) You'll pick up the hotel's business card and put it in your pocket when you check in, later. Your son will carry one too.

I admit that I'm male, but I've been to Paris a dozen times and have never had anyone try to rob me.

Gare de Lyon--it's a super busy bustling station with two large track areas. I'm not sure why someone said smaller or less bustling. That's been our arrival and departure station for the last forty years; we live on that line, my in-laws lived on that line. Ten pm isn't late in Paris. People go to dinner at 8. In fact, there's a famous restaurant in the station, Le Train Bleu, near one of the sets of tracks. Yes, just walk to the taxi stand. There will be plenty of people in the station. Finally, you aren't alone. You have a 12-year old traveling companion.

Just to reiterate......make sure you get on the offical taxi stand line. Ignore anyone asking if you need a taxi.

Unless things changed since 2020 (I've not been using Gare de Lyon as much since then), illegal taxi scams and touts are non-existent at Gare de Lyon so that's not a concern.

Thanks for the advice, all. I forgot how late things go in Paris, per the point about dinner. We were at the lawn by Loulou's a couple of years ago to watch the Eiffel Tower light show from afar, and I couldn't believe how many people, locals included, were hanging out on the lawn after 9PM.

Anyway, since I am on a thread with people familiar with French trains, does around $75 a ticket for Nice to Avignon and another $75 for Avignon to Paris (both one-way and standard class on Inoui) sound right? This is for early July. I'd like to get these booked, but not sure these are the best prices.

EDIT: originally the second ticket said Avignon to Nice, but that was a typo. It's Avignon to Paris.

75 sounds expensive for Nice to Avignon.
75 is good for Avignon to Paris.
In any case: prices don't go down.
Make sure you book on SNCF Connect, the official ticket booking portal of the French Railways.
If that fails, trainline for a small fee. Rail Europe as a distant third option. Other retailers are more dodgy.

Since ticket sales opened last week for summer tickets, prices will only go up, not down. So if you see a price you like now and are sure on your times, go ahead and buy it.

(And I concur with the others that the Gare de Lyon is fine on a summer's night. At 10 pm in July, it's probably still dusk, although I guess I should check timeanddate.com before saying that !)

Thank you all so much.

one more question, this has been so helpful. Seat selection is either no preference or club seats for four. If I pick no preference, am I still going to be seated with my son? What is the option other than the club seats for four?

You would be fine taking the metro if you preferred. 10 in Paris is when people are getting done with dinner and the streets are full and the metro is full until it closes after midnight. This is not a dangerous city (pickpockets yes, but muggers pretty much 'no' and you are at greatest risk of pickpockets at noon at the Louvre -- just make sure you don't have anything of value where it can be accessed by others). You would be fine walking to your hotel if it were near by. You would be fine on the metro. A cab is certainly fine. There is nothing to fear and a child is at no greater risk than anyone else.

Yes, you'll still be seated together even if you pick no preference.
The other option is pairs of side-by-side seats, but if you can't see it it could mean your chosen train is filling up, so book soon!

The last time I arrived at Gare de Lyon the taxi line was crazy. Lucky for me, I stay near Bastille when I am in Paris and that area is within my walking distance from the train station. However, not for safety reason but rather for convenience, I recommend https://www.sncf-connect.com/en-en/train/train-services/mon-chauffeur. You can skip the taxi line. The last time I used the service, I was scheduled to arrive at Gare de Lyon from Milan with two children at around 9 PM. Not late by any means but the train was delayed about an hour (still not late) but I arranged for the car service because I had to drop them off near Gare St. Lazare and I did not feel like dealing with either the metro and walking or the taxi line.

Thank you - I will look into that service! It will be late and we will have a lot of stuff.

We just used tge G7 Paris app to book a taxi from hotel to Gare de Lyon. We could choose the size of the taxi because we also have lots of luggage. It was very reasonable only €20 for a 6 km ride.