Bilel Hi! This is a known issue. This is because bunq transfers money to Boursorama as an Instant Payment. But this bank wants the first transaction to be a regular SEPA transfer, not an Instant Payment. Unfortunately, there's no way to force a regular SEPA transfer.
Boursorama should just accept Instant Payments 🤷🏼♂️
This is a known issue, but there's no solution at the moment.