The other steps
Contact the EDF-GDF agencies and the telephone company on which you depend to cancel your subscriptions and provide the meter reading.
You can do this several days in advance, if you know the exact date of your departure.
Also inform your insurer of your move. You can either transfer your contract to your new apartment or stop it.
Contact your new address as soon as possible at the Caisse d'Allocations Familiales, the Caisse Primaire d’Assurance Maladie, and Trésor Public, your bank, your school, etc.
To lose no mail, make a follow-up request to La Poste