Besides costly estate agents (Agences Immobiliers), https://immoweb.be is the de-facto monopoly for the local online housing market.
See some hints on Tenant duties in the annex.
Household Help
For household help, the Titres-Services voucher system is a method of payment subsidised by the Brussels-Capital Region. Managed through various accredited agencies, it enables any adult resident in the Brussels-Capital Region to take advantage of services at an advantageous price, whether they involve cleaning, ironing, shopping or transport for people with reduced mobility. Many advantages include insurance, holiday and sick pay for your help. Information and inscription (French/Dutch): https://www.titre-service.brussels/