Hi famousbill19!
Below is the updated/confirmed schedule for Masses/services during Holy Week and Easter. In an effort to "put everything in one place", I also just created a separate forum topic with all the details about visiting Notre Dame during Holy Week and Easter: https://community.ricksteves.com/travel-forum/france/a-guide-to-visting-notre-dame-during-holy-week-easter-resource
No time slots/reservations will be available from Sunday, April 13th until after Sunday, April 20th, and there are no advanced reservations for Masses/services.
If you are attending a Mass/service, you can enter in the "Mass and services only" queue. It's on the right side (if you're facing/looking at Notre Dame), and it's marked by a small white sign. Entrance starts 30 minutes ahead of the start time of whichever Mass/service you're attending. But if attending is really important to you, I recommend arriving 1 hour in advance, due to the large number of people that are expected to attend. Entrance is still subject to the available capacity inside the cathedral.
Certain services are at different hours than usual and/or are not happening during Holy Week/Easter (see individual notes beside each one):
Sunday, April 13th (Palm Sunday):
- Morning Mass/Palm Sunday Mass at 8:30am
- International Mass/Palm Sunday Mass at 10:30am (instead of the usual Gregorian Mass at 10:00am)
- International Mass/Palm Sunday Mass at 12:30pm (instead of the usual 11:30am)
- Diocesan Mass/Palm Sunday Mass at 6:00pm
Note: There is no Lauds and no Vespers
Monday, April 14th:
Tuesday, April 15th:
Wednesday, April 16th (Spy Wednesday):
- Morning Mass at 8:00am
- Afternoon Mass at 12:00pm
- Evening Mass/Chrism Mass led by the Archbishop of Paris at 6:30pm (instead of the usual 6:00pm)
Note: There is no Vespers
Thursday, April 17th (Maundy Thursday):
- Tenebrae at 9:00am
- Evening Mass/Mass of the Lord's Supper led by the Archbishop of Paris at 7:00pm (instead of the usual 6:00pm)
Note: There is no Morning Mass, Afternoon Mass or Vespers
Friday, April 18th (Good Friday):
- Tenebrae at 9:00am
- Veneration of the Crown of Thorns from 10:00am until 5:00pm
- Procession of the Stations of the Cross at 12:00pm (outside on the parvis)
- Procession of the Stations of the Cross at 3:00pm (inside Notre Dame)
- Evening Mass/Celebration of the Passion of the Lord at 7:00pm (instead of the usual 6:00pm)
Note: There is no Morning Mass, Afternoon Mass or Vespers
Saturday, April 19th (Holy Saturday):
- Tenebrae at 9:00am
- Easter Vigil at 9:00pm
Note: There is no Morning Mass, Afternoon Mass, Vespers or Evening Mass
Sunday, April 20th (Easter Sunday):
- Morning Mass at 8:30am
- Lauds at 9:30am
- Gregorian Mass at 10:00am
- International Mass at 11:30am
- Ecumenical Celebration of the Mystery of Easter led by the Archbishop of Paris at 4:00pm
- Diocesan Mass at 6:00pm
Note: There is no Vespers