It's only $5 to enter and they have hourly guides in English and French. So time your visit here at the top of the hour for the English tour.
I learned a lot of history with this basilque and you learn a lot of it through the tour. You can still do your own self tour, take pictures, and just walk around and appreciate the different architecture styles because of the many remodelings its gone through the years. Don't forget to check out the chapel behind the main alter too.