We used a large locker at the Gare du Nord location. There were 4 of us and we managed to put our 4 mini suitcases in the one large locker. Result! 😀 and easy.
We looked in one of the medium lockers at the location as a girl there was having problems shutting the door on her large suitcase, so really measure exactly as there is no give on the doors. We had no troubles at all with our experience, but we did hear two separate conversations at the location with people there who were having problems talking to the automated message service on their phones as they couldn’t access their lockers - but I don’t know their stories.
For us it was very easy to book and find, and Bounce gives easy instructions as you go through the locker experience.
Would use again.