[Bancontact] Do both payer and receiver have to be with the same bank to be able to execute a payment?

Documentation Bancontact
1

No, everyone can pay to or receive from everyone as long as both parties have a Bancontact card issued by one of the 20 participating banks.

https://www.bancontact.com/en/faq/do-both-payer-and-receiver-have-to-be-with-the-same-bank-to-be-able-to-execute-a-payment