In housing, there is. It’s much harder to discriminate in housing than elsewhere because the standards of objectivity and documentation are so much higher. The FHA is very strictly enforced. Fair Housing inspectors make random stops to mystery shop, files can be and are audited, and anytime there is a FH complaint, a company (not just the property) will be investigated.
Sometimes, people you turn down for legit reasons will suspect discrimination and send their own friend or family member in to test the property. If their friend is approved, you can bet you’ll get a formal complaint. If you’ve been fair and honest, no problem. But if you haven’t, the company and the individual employee are both liable.
If you deny someone an apartment, you must have objective documentation as to why - credit, income, or a background check. You must offer the same remedies (co-signer, higher deposit, pay the lease upfront) to everyone.
Most reputable companies use leasing software that easily maintains all of these records because it’s industry and government standard. If you call a leasing office and they tell you they have no one bedrooms available, and your friend calls 5 minutes later and is told they do, the software will show whether or not a hold was cancelled and something became available in that span. If it didn’t, or if the company just keeps bad records, they’re open to a lot of trouble. You have to keep records of what is available and when, down to the time of day.
I was an assistant property manager for several companies while I did my undergrad. Complaints, investigations, and legal penalties are all very common. Most complaints are bunk, but certainly not all. And it costs nothing to have a property investigated if you feel you’ve been discriminated against; no lawyering up required.