Door-to-door canvassing and energy renovation of homes are subject to surveillance by state services. To protect against potential fraudulent actions, the General Directorate for Competition, Consumer Affairs and Fraud Control (DGCCRF) advises consumers not to sign anything on the same day.
Be wary of companies that claim to be mandated by a public body, because public services never approach you, whether by Internet, by telephone or at home. Do not transmit your personal information (banking and tax). Check the financing of the work by a loan.