I thought I would start with the most famous church in the world. I know that many of you will know that St Peter's in Rome is the most famous or maybe St Sophia's in Instanbul. However, I haven't seen St Peter's and St Sophia's is no longer a church. That makes the Cathedral Church of Our Lady (who presumably is also the Blessed Virgin Mary, the Theotokas, God's bearer, aka Mary mother of Jesus) in Paris as my occupier of the role.
Among the most important observations about this magnificent building is that it is a working church, it is in the most romantic city in the world (easy to prove) and it is very, very ugly from the front. All of the best representations of Notre Dame in Paris are either drawings in Disney cartoons or pictures taken from the river looking west. I still think it is an amazing church and deserves its reputation but it is difficult to get a decent photograph of a loved one using the western end as the background. It has a huge frontage with a very flat square look that is exacerbated by the stone railings that run between the two massive towers. These hide any roof line that would provide an interesting angle in your visual composition. The plaza out the front is fairly dusty and featureless in the way that is typical for Paris as well. The busking acts can be quite good.
Once you go inside the feel of the place is very different. There is no fee and although the queues can be very long, they move quickly. Once in the church the crowd moves up one side, around the back and then down the other and out the door. To follow the crowd would be a mistake even if they do manage the whole building quite quickly.
Firstly you can buy big candles to light and remember and pray. Not everyone will want to pray but the church is dark and the light means something even when it is massed with the other lights in the candle stand. If you have anything in your life that deserves that candle, then pay your Euros and, more importantly, give some time over to a moment thinking about that thing. If I were less cynical I would suggest that this was a building purpose made for it.
Another thing you can do is go to the centre of the church and sit down. This is a big space hollowed out of a big city and in the dark it is easy to ignore the circling crowds out from which you slipped.
For all of this silence and reflexion talk, Notre Dame is not made principally for introversion. This is a metropolitan cathedral built as a demonstration of wealth, power, civic unity and as a statement of the city's most powerful people of their commitment to God (and perhaps their expectations of God's con-commitment to them). If you want peace, go to the country side. The window glass is extraordinary and quite a bit of it is just short of a thousand years old. The south and north facing round (rose) windows of blue glass captivates me for as much time as I have.
As you head to the back there is a wooden church within the church (known as the choir stalls) which is used for smaller services. In some cathedrals it fully enclosed with a wooden or stone screen at the front but here it is open at the front so you could see right into it when you came in. The backs of the stalls, as you walk around, have wood medieval carved scenes from the Life of Christ (as it is known) which are not realistic but instructional. Even when the crowds are in full flow, you can still pause at each one. During my last visit the flow took me around them in the reverse order to the story so I wandered back against the flow and looked at them a second time in the right order.
In terms of church services and the like, I can't comment. I have been in the building during the Saturday evening vigil mass. The cathedral remained open to the tourists and the people attending the service sat in the middle towards the front. The service was conducted by a single priest and two singers and it felt as if they didn't try and take over the space. It was a bit wan. However, it was midsummer and many churches lose choirs, clergy and other staff leaving services fairly lean.
One thing that always seems to be true, and this is the only church I have ever seen this, is that two or three of the little side chapels each have a robed priest sitting in them during the day. The chapels have been glassed in and have a desk and comfy chairs giving them a functional privacy. There always seem to be people making use of this facility. If you have a problem and want to see someone then this place is open for business.
This cathedral is the heart of Paris regardless of your views of the roles of Louvre, Eiffel Tower, Arc de Triumph or even the Hotel de Ville. It certainly looks the part and through sympathetic management of the space, free entry and easy availability of the staff it keeps its religious function open to all.