Hi @Aude ,
Is is feasible ? For my colleagues it is not possible to collect attachment figures.
From the perspective of Exchange server side, agreed with your colleagues that no, it's not feasible to get the attachment data like the number of attachments per mail or the format of attachment.
Supposing you are using on-premises Exchange server where message data is usually retrieved from message tracking logs, attachments related data are not recorded in the logs. See Fields in the message tracking log files.
By the way, considering that Power BI is currently not supported in Q&A, if you would like further help in terms of BI, you can also visit the dedicated community below:
Microsoft Power BI Community
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