MAIOT: New online procedure for declaring modifications to an ICPE or IOTA

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As a reminder, under articles R. 181-46, R. 512-46-23, and R. 512-54 of the Environmental Code, any significant modification made to an installation classified for environmental protection (ICPE) or to installations, structures, works, and activities (IOTA) must be declared to the prefect by the operator. ‍

Following the review of the notification, the inspection authority determines whether the modification is substantial or significant:

• If the modification is considered substantial and not merely significant: a new environmental authorization or registration application, or a new declaration, will be required;
• If the modification is not considered substantial: the application may result in an acknowledgment letter (acting as an authorization for the modification), a supplementary prefectural order setting new requirements for the modification, or a refusal.

A note from the Ministry dated December 20, 2021, clarifies the assessment criteria for determining the nature of the proposed modification.  

Since March 5, operators of an ICPE or IOTA have the new option to declare modifications to their facilities electronically.

This option applies in particular to:

• ICPE subject to the authorization or registration regime;
• IOTA subject to the authorization or declaration regime.

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This online procedure is not mandatory but is highly recommended to help route files more effectively, facilitate the issuance of an acknowledgment of receipt, and shorten processing times. Operators therefore have the choice of completing this process online or by postal mail.

Once the process is complete, a receipt will be issued by the administrative authority.

Please note that the following requests cannot be made via the MAIOT online procedure:

• Change of operator;
• Transfer of authorization;
• Declaration of priority or grandfathering of acquired rights;
• Updating the soil pollution status for every significant change in operating conditions for certain facilities (geological carbon dioxide storage sites, high-threshold Seveso ICPE, quarries, waste storage facilities). This status report must be submitted by the operator to the prefect, the mayor of the municipality concerned or the president of the EPCI, as well as to the owner of the land on which the facility is located;
• Total cessation of activity.

These must therefore be sent directly to the processing department (prefecture or town hall) by mail.

This online procedure is all the more relevant given that the Council of State, in a recent decision rendered on April 8, 2026, considers that notifications constitute requests for modification of the operating authorization and are not subject to the "silence equals consent" principle under Article L. 231-1 of the Code of Administrative Justice. Consequently, silence maintained by the prefect for more than four months from the date on which the modification project was brought to their attention constitutes an implicit rejection of the request. The date of the notification made via the online procedure will therefore trigger the 4-month period.

Finally, declarations currently being processed do not need to be resubmitted on the platform.

The online procedure is accessible via the following link: https://entreprendre.preprod.service-public.gouv.fr/vosdroits/R75904.

A frequently asked questions section to assist with declarations is also available.