Hi @André LE GAL,
You can use the Send-MailMessage cmdlet to send mails from within PowerShell. Per my test, multiple attachments can be included in this method.
Below is a sample code which can be run from the command prompt:
powershell send-mailmessage -to '******@contoso.com' -from '******@contoso.com' ^
-subject 'Test email' ^
-SmtpServer 'smtp.contoso.com' ^
-attachment 'file1', 'flie2'
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.