We would love ti go to here or to catacombs on way to airport CDG, but need place to store mid size suitcases. Thanks
Sewer tour loved by my 8 year old but OMG it was stinky. I mean really stinky. I thought as a nurse I had smelled everything at its worst. Not so. Take a bandana with a little cologne or body spray on it to get you through. You wont regret it.
Some railway stations store luggage. The man in www.seat61.com has a list: http://www.seat61.com/luggage-on-european-trains.htm#Left luggage lockers in Paris
It's likely that you will have to go out of your way anyhow, so you might think about leaving your bags at the hotel.
Oh, PS: I found the aromas in the sewer museum quite mild and the place is intriguing for the mechanically-minded. To make a French pun, chacun a son egout.
The tunnels of the Sewer Museum only handle ground water runoff. If you go past the barricades you can wander all over the city and see exactly the same thing. The worst stuff comes from everwhat was in the gutters. It all gets dumped into the river eventually (look at the grates along the quais to see where). Blackwater/greywater sewage is moved in the closed pipes that you'll see if you look around. It goes to a treatment plant. It's just like hopping down a manhole - - you're not going to slogging along in household sewage. It tends to smell better when it's cooler or after it's rained.