St Chapelle concert - walk in tix?

I used to buy tickets no more than a day in advance on sight. I'd just go by the venue and buy tickets either earlier the same day or one day prior to visiting. In Paris, I got great use out of the Museum Pass and just arrive when the lines were short.

That was pre-Covid. September will be my first trip back to France since 2018. Post Covid, I've been to Scandinavia, Germany, Austria, Czech Republic, Hungary, Spain and Italy. So far, it looks like the world has changed. In big cities, advance ticketing seems to be the new normal. I'd overgeneralize by saying there are far more tourists, and those tourists are booking tours. The tours, in turn, are sucking up all the tickets - leaving few, if any, available for walk-in traffic. I booked tickets in advance for St. Chapelle this trip.

I had reserved a ticket one time and apparently it did not go thru. I got there and they had me stand to the side until everyone was in and then they had a few spaces left. IF this is something you want to do (and it is AWESOME) I'd get a ticket at least a few days ahead.