Button names are shown as in the French interface.
1
Open the card editor
In Cartes de Visite, click Modifier le profil on your card, À propos tab.
2
Change the address
In Informations de contact, Adresses e-mail section, edit the address. Use Ajouter un e-mail to add another one.

3
Save
Click Enregistrer la section À propos, then Mettre à jour la VCard.
The login address is hidden on your public card unless you choose Affiché.