Montpellier or Toulouse?

Do you plan to just sightsee locally, or will you take day trips? If planning day trips, will they be by public transportation?

For local sightseeing, I think there is more to see in Toulouse, though I won't be surprised if Bets proves me wrong.

Thank you, acraven! I think both--local sites and exploring a bit, preferably by public transit or maybe a day tour.

I spent a week in Toulouse last September which included two day trips - one to Carcassonne , and one to Albi . The cathedral in Albi was stunning , and the major draw for me was the Lautrec Museum . Henri De Toulouse Lautrec was born in Albi , and the museum exhibits an exceptionally large collection of his work , well worth a visit

About Toulouse I would add to Steven's good suggestions the possibility of taking a mini-cruise on the "Canal du Midi" such as this one (there are others)

https://catefifi.com/

Toulouse being the European center for the aeronautical and aerospace industries, in case you are interested you can also visit the Airbus factories

https://www.manatour.fr/en/airbus

(but I do not recommend the Space Museum)

If you have children (but not only) You can also go see "La Halle de la Machine". which is a kind of amusement park but probably not what you expect. I don't know how to describe it.
See more here:

https://www.youtube.com/watch?v=LNuK6TIw_QQ

https://www.halledelamachine.fr/en/1203-2/

About Montpellier there are also plenty of things to see and do.
The atmosphere is different, more "southern" with the Mediterranean Sea not far away.
The charming town of Sète deserves an excursion with its fishing port, the Thau archipelago, and its oyster beds.

https://www.tourisme-sete.com/

You will also be very close to the Camargue region and the city of Arles (80Km)

https://www.france-voyage.com/tourism/arles-122.htm

In fact you should spend a week in Toulouse and another in Montpellier.

You can't go wrong either way. We spent ten days in Toulouse and enjoyed it.

Montpellier has three large art museums and several smaller ones and galleries: Musée Fabre (all periods), MOCO (contemporary), and an art brut museum (outsider art). In addition, there's an archaeological museum in what was a nearby Roman settlement https://museearcheo.montpellier3m.fr/
This is on the way to the beach.
The oldest medical school still in existence is in Montpellier; both Nostradamus and Rabelais got their MD degrees there! Tours available.

There's all kinds of dining from burgers to some Michelin recommended and a few stared restaurants. There are a lot of places and esplanades with cafés and restaurants.

In additon to the day trips Jolui mentioned, there's also Nîmes with its Roman ruins and Roman museum. The Office of Tourism can arrange trips to the medieval monastary of Saint Guilhem du désert, the Pic Saint Loup, and the vinyards. Uzès and the Pont du Gard aren't far but you'd need a car unless you found an organized tour. The train back to Paris is 3 hours from Montpellier.

Thank you, JoLui and bets! I appreciate all of the details you are sharing. The description of Montpellier being more southern/Mediterranean is intriguing, because we have really enjoyed our time in southern Italy and Turkey. And great idea about visiting both! We'll have to save one for a future trip. (smile)