What's the difference between filing a regulatory complaint against a professional and suing them in Ontario?

A regulatory complaint asks the professional's governing body - the Law Society, CPA Ontario, the real estate regulator, or similar - to investigate whether the professional breached their rules of conduct. If the complaint succeeds, the outcome is discipline: a reprimand, fines payable to the regulator, licence conditions, or in serious cases, suspension or revocation. None of that puts money in your pocket. A civil lawsuit, by contrast, is your route to actual compensation for the financial loss the professional's conduct caused you, decided under the ordinary negligence or breach of contract framework in the courts.

The two processes are independent and can run at the same time without one blocking the other, though the standards and questions each one asks aren't identical - a regulatory finding of misconduct isn't automatically proof of negligence in a lawsuit, and a regulator declining to discipline someone doesn't mean a civil claim would fail. Many people pursue both: the complaint to hold the professional accountable and protect future clients, and the lawsuit to recover their own loss. If your main goal is getting your money back, the civil claim is the process that actually does that.