I want to attend Mass at Notre Dame and wonder if there is a separate entrance for those only wishing to attend service.
We attended Mass there several years ago. Just go thru the main enterance and find a seat. It was a very unique experience, as is attending Mass at the Vatican.
All the tourists spoil the mass at Notre Dame; my favorite mass in Paris is at St. Sulpice. It's spectacular!
Bypass the lines & walk up to the door where all the tourists are entering. Tell the attendants in French that you would like to attend Mass.(Je voudrais attendre en mass si vous plais. Or something like that.) Priority is given to those who attend services. They will most gladly lead you to the center aisle of the Church where you will find a seat. Don't worry about the tourist noise. The center columns muffles the walking and murmuring sounds created by them. My opinion is a bit different from Joe's though I certainly understand where he's coming from. To me, the noise is rather rhythmic & soothing.
I have been to many masses in Paris. I like Notre Dame, but the tourists do get in the way. The best is to get a seat up front. It is one of my favorite spots in the world, and the mass is lovely. Sacre Cour is another nice place for mass. San Suplice is OK, and the organ concert after the 11:00 one is great, but the church is not as dramatic. As said above, just go in the main doors and take a seat. You will be glad you did.
You might also enjoy the International Shrine of the Miraculous Medal which has a lovely chapel and also the preserved remains preserved remains of St. Catherine Laboure. The address is 140 rue de Bac and is only a few blocks from metro station.