Hey lots of cool places to run I can join if you want.
Check out the banks of the seine it's a pedestrian area about 10Ks on each side easy access from the ninth.
A few parcs, bois de Boulogne (south west) has some "trails" or a small lake that you can lap around about 3ks(it also has a "closed" area for cyclists a loop around a horse race track, called hippodrome de Longchamps, with some decent pavement 3.6k pretty heavily populated on the weekends with packs). For some "hills" try Buttes Chaumont north east. Finally my favorite parc is east, bois de Vincennes, it's the biggest you can easily get 15-20ks without running in the same place twice.

https://www.dcrainmaker.com/paris-swim-bike-run

If you look to run with a group of runners, you can google “let’s run Paris” on Facebook.
We run every saturday morning 9 am from Jardin du Luxembourg for 14 to 25 km depending of the week, we have 4 pace group ranging from 4’30” per km to 7’/km and the course is different each week.
The group is a mix of expat and french.
We also have a 10 KM every Monday evening 20h00 from Place de la Nation.

One of my favorite things to do!!

I think you start at the Jardins Luxembourg go down to the Seine, along the bank cross over at any bridge to the Louvre, up the Champs Elysee and then down towards the Eiffel Tower. Back along the Seine.

Super touristy...but that’s the point :)

Awesome! Thank
You!