Not all church buildings were as nice as Notre Dame, but yes, everyone after 1215 (well, Christians, which was almost everyone if you are talking about western Europe) was required to go to church at least twice a year: once to receive the Eucharist, usually on Easter, and once before that, to say confession and receive absolution so when they received the Eucharist it would not be a sin. In fact, the history of pastoral care (priests instructing average Christians) in the late Middle Ages is pretty much the story of priests trying to get people in church more often! Probably if you were poor you didn't get to sit down, but you were more than welcome inside.

Beggars in particular would often flock to the funerals of local glitterati and nobility, in hopes the deceased would have arranged to have money distributed as charity for the good of his soul. In some cases, in order to make sure enough people showed up for the deceased soul to receive the maximum benefit for his generosity, the amount to be distributed was announced in advance!