City Locker – a genius idea. Three locations in the city where you can check your luggage in either while waiting to check in or after you’ve checked out of your accommodation. They’re open from 8am to 10pm, 7 days a week. You have to book online in advance with a credit card and they’ll send you a code so you can access your locker without the need for staff.
You can leave bags and suitcases into a secure lockers at Saint Lazare Train station in Paris. The price is 12€/day/locker. https://www.lockers.fr/en_US