A beautiful church that you have to check out during your stay in Montreal. We paid the $5 (adult) admission to go inside and really enjoyed walking around, taking a bunch of pictures and listening to the complimentary English informational tour that was offered.
We visited on a weekend around 11AM and it wasn't too crowded at all. There was a wedding happening in the back chapel so during the tour, we were unable to see it. There's also bathrooms in the church and yes, it's clean.