I’ve used https://hippocketwifi.com/en/
Hippocket Wifi on multiple trips and have been very happy. I carry a portable charger to charge my phone and wifi unit toward the end of the day.
The plan I use is the 59 euro for the week. The unit will support up to ten devices, so it’s possible to share if you’re going to be near the person you’re traveling with most of the time.
It seems there’s more and more need for internet access while out and about in Paris. Maps, Metro apps, restaurant reservations and more. It’s not required but I’ve found it to be very helpful.
Update 1/19/24 : for Spring 24, use the code FLASH20 for 20% off your rental. I’m not sure of the exp. date if any