Arriving from London on Eurostar and need storage for the day so we can go to the Louvre. We've bought tickets to the Louvre for a certain time and want to make sure we won't have difficulty getting one of the lockers at Gare du Nord...can't be late for our time slot into the Louvre!
There's no way to reserve luggage lockers at Gare du Nord and you're not guaranteed a locker as there's not massive amounts of space. The few times I've used Gare du Nord baggage storage, I haven't had problems with space. There are also third party providers outside of the station as well you can use such as Stasher, Nannybag, Luggage Hero.