Free 1st Sundays in Paris specifically November

Ok it was not November but we just got back first Sunday January 7 2018 all the museums were crowded; the museums you mentioned were crowded as well on non free days;

On free day you should go to the Cluny and the other great museums in Paris that tourists don't know so much about

Any museum you chose on free Sunday, get there early. Lines form to get in by noon.

There is no Mass in Sainte-Chapelle. It is a State-owned facility.

There will be a lot of people going on the 1st Sunday of the month.
For that reason, I'd split the difference - go to your favorite museum, then buy the Museum Pass for the rest.
You always have to wait in a Security line, even if you have the Museum Pass.
I wouldn't bring a backpack or anything, which will slow things down immensely.

For that reason, I'd split the difference - go to your favorite
museum, then buy the Museum Pass for the rest.

How do I split the difference? Let's say I go to Cluny on the 1st Sunday in November as was suggested first thing in the morning. I should buy a Museum Pass to be used on that Sunday too if I decide to go to Musée d'Orsay in the afternoon? Wouldn't that be a waste to use a Museum Pass on a day when it's a free Sunday? Or is there a benefit that I'm missing? I'm confused.

chexbres meant to buy a pass for the rest of your days, not the rest of your museums.

If you show up 1/2 hour or more before opening, you will save a lot of waiting you would have had to do otherwise. We went to the Concierge first thing on free Sunday last October because I hadn't visited it before. There was a manageable line 30 minutes before opening. 15 minutes later, it was 3 or 4 times that. Later we went to the Orangerie, which wasn't too bad. We were planning to see d'Orsay, but the line was horrible so decided against it. On free days, you're getting in line with lots of locals as well as visitors so it's going to be crowded. My French girlfriend thought I was crazy going before opening but looked at the line behind us, when it opened, and decided it was a great idea. The 30 minutes we waited before opening probably saved 1 1/2 hours or more waiting if we showed up at opening time.

I guess I'm still confused. My apologies. So if I used a musuem pass on that free Sunday for Musée d'Orsay in the afternoon, would I still bypass lines?

No. Everyone is in line only for security, so you can’t go ahead of the others. A museum pass is the same as a ticket in hand but it doesn’t give priority for a security line. Therefore, a museum pass is useless on free Sundays since everyone needs to wait in the same security line.

You should plan to not have an active pass on free days, it's a waste.

When you are attending on a free day, there will only be one line, for security, no one needs a ticket. Sometimes they will print out a complimentary ticket for you to keep track of the number of visitors. There will always be security, and usually it's a bottleneck and creates a line. You can get through faster if you don't carry a bag and have your cell in your hand but it still depends on who you are behind.

On other days it depends on where you are going. Some places, you can virtually walk right in by going straight to security, it's obvious the line is for tickets. Some places there is one line, it doesn't divide into those with/without passes or pre-purchased tickets until after security and that's not until you are inside - I don't think you can politely walk past all the people in line outside. Other places, like the Louvre have several lines - one of them for passes which is usually shorter than for people who need to buy tickets and it leads to its own security line.

I'd suggest that you go on Sunday to your most favorite museum, and purchase the Museum Pass for the rest of the time that you are in Paris.

Continental, here's your problem with the Paris Museum Pass....

I picked this up from a previous post:

I'm planning a trip in November in which I arrive in Paris on a
Thursday and stay until the following Tuesday.

Additionally, you are planning a day trip for Saturday:

My day trip (Saturday) via rail will center on a grand Gothic
cathedral. I've been to Chartres once before in 2002 but there's no
reason I would not return to see those stained-glass windows again.
I'm also considering Amiens, Rouen and Reims so far.

As above, we've established that a pass is of no use to you at all on Free Sunday for the attractions you list, and as your plan stands right now, you do not have two consecutive full days in which to use it. If you weren't day-tripping on Saturday, you'd have all day Friday + Sat. to make good on it. You might consider shuffling your itinerary and take your day trip on Monday instead? I have not checked the others but Chartres is open on Mondays.

Thank you all for your advice and providing info as to how the Free first Sunday works.

Kathy, I was either going to take a day trip on Friday or Saturday. On my last full day of the trip which is Monday, I want to be in Paris. So it looks like the Museum Pass won't work. Since there will be lines on that free Sunday especially at popular museums like the Louvre and d'Orsay, I will go to museums that may not be as busy like Cluny which I really want to see and maybe St Chappelle in the afternoon. I would like to go to mass on Sunday morning in a Gothic church so by the time I would get to the popular museums, the lines could be very long.

I always travel with a day tote bag so I'll be subject to security lines. I keep an umbrella, sweater, maps and a travel book in there. I do wear a money belt where I store credit cards, big cash and my passport. It hasn't been an issue when I've gone through security at London museums.

If you want to go to Notre Dame, there is a "Messe" (Mass) sign on the left side of the door.
You just walk right in.

I would like to go to mass on Sunday morning in a Gothic church

OK, so as your day trip was to see one of these churches outside of Paris, why not do that Sunday and use the 2-day museum pass on Friday and Saturday?

I also want to enjoy outdoor/indoor markets and peruse book shops. I hadn't considered doing that on a Sunday as I assumed they would be closed. If that's not the case, I'm open to reconsidering.

In general, for most markets, indoor and outdoor outside of tourist areas, Sunday is the big day until about 2 pm when most close. Bookstores in neighborhoods are generally open until 2 pm also as are most little stores. In my neighborhood for instance, on Sunday only the Monoprix is closed. Sunday until around 2pm is a busy time in Paris neighborhoods. Regarding the area in which you are staying or which you want to visit, you could google specific markets and book stores to get their exact hours.

In areas where there are many store openings and markets on Sunday, those businesses are generally closed on Monday.