If you want your belongings to be cared of for some time, you can use left luggage offices at Parisian railway stations. Most of the railway stations in Paris feature automatic luggage cupboards (“Consigne” in French, look for this word at signs). You can choose a locker you like and pay for your possessions storage via a terminal. That device will give you a ticket, please, keep it as it contains your locker number and later you will be able to get your luggage back.
Please, take all necessary precautions; do not store valuable things in the luggage cupboards. Mind that you cannot leave a bicycle in a left luggage office.
Prices. The price depends on a locker size: €3.40, €5 or €7.5 for 72 hours. Some railway stations in Paris have the following fee schedule: €4.50 for one piece of luggage (a suitcase, a box) or €5.30 for a bicycle or a wheelchair (for 24 hours).
Parisian railway stations with left luggage offices:
The Eastern Railway Station (Gare de L’Est): open from 6.00 to 23.45;
The Railway station of Lyon (Gare de Lyon): open from 6.15 to 22.00;
The Railway station of Montparnasse (Gare Montparnasse): open from 7.00 to 23.00;
Austerlitz Railway station (Gare d’Austerlitz): open from 7.00 to 23.30;
Saint-Lazare Railway station (Gare Saint-Lazare): no left luggage office;
Bercy Railway station (Gare de Bercy): no left luggage office.
In addition, you can find a baggage room at Disneyland:
Station RER CHESSY MARNE LA VALLEE PARCS DISNEYLAND: the room is open from 7 to 22.00.
Disneyland Park: the left luggage office is open from 8.00 to 45 minutes after the closing time. Also there are some lockers in museums, but they suit ladies’ handbags more than heavy suitcases.