By Mathieu Rosemain PARIS, Dec 9 (Reuters) - Facebook-owner Meta holds at least a 3% stake in EssilorLuxottica, ​a board director at the European firm behind ‌Ray-Ban glasses said on Tuesday. The Meta stake has previously been reported from ‌sources but not confirmed by either firm. The two companies are working closely together on Ray-Ban Meta AI-powered glasses. Jose Gonzalo, executive director at French state-owned investment bank Bpifrance and ⁠an independent director ‌on EssilorLuxottica's board, s ...