Datananas Outbound allows you to connect to your Gandi account.
For this purpose:
1. Go to your Settings > Email
2. Click on Gandi
3. In the field that appears, complete all Email, IMAP and SMTP host, port, username and password
4. Click on Connect
If the synchronization doesn't work, select Other, and configure the advanced connection (cf. article Synchronize my mailbox with SMTP/IMAP )
For more information on your sending email quotas, go to the following article: Sending email quotas