Opale SA is 90% owned by Groupe Nacre; the other shareholders, who have been informed, do not object to its not preparing consolidated statements. Its securities are not traded in a public market, it has filed nothing with a regulator for a public issue, and Groupe Nacre publishes consolidated statements that comply with IFRS and are available for public use. Opale holds 30% of Brume SA, over which it has significant influence. Write a short note concluding on the equity method for Brume, distinguishing case facts, rule and professional judgement.