In Belgium, either you have a company number and you take it.

Either you don't have one and you have to ask your bank to have one.

Here an example :

With company number (0456 810 810) : BE12 001 0456810810

Without company number : BE69 ZZZ 050D000000008 

Here is the info from a Belgium bank page 11 (in french) for more detail.

https://www.belfius.be/common/FR/multimedia/MMDownloadableFile/Business/Themes/Sepa/MMDF Sepa Direct.pdf