XIX § 31 Liberative Prescription.

Here's a plain English summary of this rule:

If someone wants to file a complaint against a lawyer for making a careless mistake (not something done on purpose), they have ten years to do it. The clock starts running from the day the mistake happened. This ten year deadline is called a "prescriptive period," which is just a legal term for a time limit.

This rule only applies to cases involving negligence, meaning the lawyer messed up through carelessness rather than intentional wrongdoing. If the ten years pass without anyone filing a complaint or starting an investigation, the matter can no longer be pursued through the disciplinary process. This gives lawyers some peace of mind that old careless mistakes cannot be held over their heads forever, while still giving clients and others a long window of time to raise concerns if they discover a problem.