As a broad estimate, €10,000 to €30,000 excl. VAT for a scopes 1-2-3 assessment, depending on complexity, starting at €3,000 excl. VAT for a very small organisation with a simple scope. Bpifrance's Diag Décarbon'Action funds 40% for SMEs with < 500 employees (company share €6,000 excl. VAT).
Read the source article: Executives' carbon footprint: the executive committee's share