You won’t find this in any guidebook. At least, I never have.

Not one of my books lists the Chapel of Our Lady of the Miraculous Medal (Chapelle Notre-Dame de la Medaille Miraculeuse). That tip I got from a fellow flight attendant. Of course.

In this well-hidden and modest sanctuary, you will find the “incorrupt” body of Saint Catherine. In other words, her remains have never decomposed.
Sister Catherine died in 1876. In 1933, her body was exhumed for a ceremony of beatification, the first step towards canonization (sainthood). To everyone’s surprise, Sister Catherine was found intact 57 years after her death. Today, you can find her body (147 years after her passing) encased within a glass casket to the right of the altar.

So who was Sister Catherine?

Saint Catherine Laboure, Our Lady of the Miraculous Medal, gave the world (with the Virgin Mary’s help) this medal.

The very medal you will commonly find on rosaries.
You see, while in seminary, she was visited by the Virgin Mary three times. Mary gave her a mission to have a medal struck. A vision formed in Catherine’s mind, an oval picture exactly as the front and back of the medal appear. She heard the Virgin say, “Those who wear it will receive great graces.”
After much resistance and doubting from her superiors, the Archbishop finally conceded and had the medals made. The medals were initially distributed during a cholera epidemic in 1832. Soon, people began referring to them as the “Miraculous Medal” following widespread reports of healing, protection, and conversion. By the time Catherine died in 1876, more than a billion medals had been distributed.
The chapel is sacred to Catholics not only because it holds Saint Catherine’s remains but mainly because it was in this very chapel that the Virgin Mary appeared. To the right of Catherine’s casket, you can even see the armchair where Mary was seated during the first apparition.

And see that gold-plated reliquary? That contains the heart of Saint Vincent de Paul. (That is another layer to the story) I won’t get into those details now, but this relic was kept hidden during the French Revolution and brought to the Cathedral of Lyon in 1805. In 1947, it was moved to this chapel.
I think you can see why the Chapel of Our Lady of the Miraculous Medal is a pilgrimage for many Catholics from around the world. For the faithful, the apparition of Mary, the presence of the relics, and the intact body of Saint Catherine Laboure make this a very holy place. It’s not a tourist attraction, so it rightly doesn’t belong in a guidebook. However, I’m including this location in my travel blog because I believe that the Catholic religion (and Christianity in general) is not a secret club. Mary appeared to Sister Catherine to help spread the word and to do the work. Faithful Sister Catherine, even in death, is still doing just that.

Saint Catherine and I invite you to visit, whether or not you’re Catholic, Christian, or even a believer.
That’s some inside knowledge of what and where to visit!
Wow, very impressive.
That is some place I would love to see next time in Paris.
I like your comment that Catholicism
And Christianity is not a secret club.