Authoritative version
The rules and contract templates are in French, which is the only authoritative version: normatys.org/contribution-de-maintien. The presentation below is provided for information only.
Main rules
- OpenNAT method, maintenance contribution, version 1, in force since 25 October 2026. NORMATYS publishes the method and keeps the OpenNAT registry.
- Published price, the same for all: EUR 1.50 excl. VAT per m² of planted and water areas per year, indexed every 1 January from 2028 on the INSEE producer price index for landscape services (CPF 81.30).
- Paid once per two-year cycle, within thirty days of the registry certificate that follows a successful control; nothing is due after an unsuccessful control.
- Three cycles (six years) minimum for the contributor, backed by a first-demand bank guarantee; each cycle is decided by the owner, with no tacit renewal and no exit penalty.
- The owner chooses and pays the certification body and the ecologist; the contributor never pays the certification body; no money passes through NORMATYS.
- One contributor per m² and per year in the registry; registry fee of EUR 200 excl. VAT per site per year, paid by the contributor.
Documents (French)
Voluntary scheme, separate from the approved nature compensation, restoration and renaturation sites known as France Crédits Biodiversité sites (articles L163-1 et seq. of the French Environmental Code). It cannot satisfy a compensation obligation.