Between €10,000 and €30,000 excl. VAT as a one-off depending on complexity (scopes 1-2-3 and action plan). Through Diag Décarbon'Action, the remaining cost falls to €6,000 excl. VAT thanks to the 40% subsidy from Bpifrance and ADEME. This is sometimes cheaper than a SaaS subscription accumulated over 2 years, with a more directly usable deliverable.
Read the source article: Bilan Carbone® software or consultancy: how to choose in 2026