Yes, a flat fee commission structure is fully legal in Ontario. Real estate commission has never been fixed or regulated as a percentage. Every commission, whether a flat fee or a percentage, is negotiated directly between a seller and their listing brokerage.
Every real estate salesperson and broker in Ontario must be registered with RECO, the Real Estate Council of Ontario. You can look up any registrant, including Hussain Lakhani, using RECO's public registrant search to confirm an active licence before signing anything.
A flat fee changes what you pay, not your legal protections. You still sign a standard Ontario listing agreement, your realtor still owes you the same fiduciary duties, and the transaction still closes through a lawyer the same way it always does.
See exactly what's included in the $4,995 flat fee, or compare flat fee vs. percentage commission.