French Ambassador François Delattre was the VIP at the International School of Boston’s 50th anniversary soiree at the Charles Hotel on Wednesday night. Among the 250-some guests at the 12-12-12 benefit were the school’s chairman of the board of trustees, Patrick Hamilton, party committee member Laurence Honan, and head of the school Richard Blumenthal. Proceeds will fund financial aid and programs at the bilingual international school.