The Basilica is well worth a visit when you go to Montreal. The outside does seem remensence of Notre Dame in Paris but it wasn't designed that well.
I would advise visiting the church definetely before 4pm as it closes then for the light show at 6.30pm. That time it is $4 to visit
Unfortunately we arrived about 6pm and could only get inside if we paid the $10 for the light show. To be honest I didn't think it was worth the money. You get headphones in either French or English and sit in one of the pews. You are given a row and seat number but it is really hard to see the numbers on the ends of the pews as it is dark.
You watch a projector screen where it shows pictures and a naration of the history of Monetral, they have actors playing out scenes which I found a little borring. If you haven't seen the front of the church yet there is a Wow factor at one point of the show. But it definitely a hollywood production that you would never see in churches in Italy or France.
You do get 15 mins after the show to look around the church and see all the statues etc....
So would definitely visit the church but I would advise you to just pay the $4 during the day








