Public Restrooms in Champs de Mars

Living near the Mall where people gather to watch the July 4 fireworks in DC, I am aware that many port-a-potties are brought in for the occasion. I thought perhaps Paris did the same thing, but I guess not:

"The very few public toilets in the area will be inundated, and nearby cafés won't tolerate non-paying visitors using the facilities, so have some cash handy to buy a drink if you need the bathroom, and have a Plan B in case of emergency (the Berges de Seine will have public restrooms)." Source: http://www.secretsofparis.com/heathers-secret-blog/what-to-do-in-paris-on-bastille-day.html

"If you plan to spend the afternoon and evening at Champ de Mars, be aware that there are very few public toilets in this area compared with the number of people who gather for the concerts and fireworks. Area cafés will not let you use their facilities unless you are there for a meal - or at least a drink.

"You can find public restrooms at Parc Rives de Seine - the riverside park along the Left Bank of the Seine." Source: https://www.parisdiscoveryguide.com/bastille-day-paris.html

I wouldn't use a public restroom in Champ de Mars on July 14th for love or money. Better to follow the advice from Rick here about purchasing something in a cafe and using the bathroom there.

I don't have any info on restrooms, but I have been to the Fireworks on Bastille Day. If you are just going for the fireworks, my advice is to arrive 20-30 minutes before the fireworks begin. Find a good viewing spot at the rear of the crowds and keep your hotel route almost directly behind you if you can. When the fireworks are concluded if you are up close it will take a long time for all the people to move out of the area. If you are in the rear of the crowds, your about face and walk to your hotel will be the easiest. Also, count on walking to your hotel because the metro and cabs will be jammed. I pretty sure the fireworks started around 10:30-11:00pm. No matter the hassles it is a great experience to enjoy.

After many hours of internet research, it really does look like there are no public restrooms in the Champs de Mars. There are only four individual sanisettes that I located, which are not even in the park, but on its outskirts. I thought "if there are playgrounds for kids, there certainly MUST be restrooms to change a diaper and wash your hands"... but I don't believe there are. I also looked at TripAdvisor reviews with the keywords "toilet" and "restroom", and those reviews corroborated my suspicion. So it seems that the French never need to change a tampon, pee in a civilized way, or wash their hands (I'm joking) when they are stuck in a park for roughly seven hours. Honestly, I don't get it. Even little parks in Michigan that hardly ever get visitors will have a building dedicated to restrooms with electricity and plumbing, yet the celebrated and much-visited Champs de Mars does not??!?

There will not be decent facilities. Just like they don't bring anything decent in in for the finish of the Tour de France on the Champs Elysee....6 hours of standing and holding it in the heat. There are a few portas but they are disgusting a couple of hours in. No fun.
I would watch the fireworks from the end of the Champs de Mars east of the tower so that you can escape in that direction where there are quite a few cafes. Towards the metro stop Ecole Militaire. You can get a coffee and use the facilities!